Fix comparison of a nullable value to a non-nullable saved value.

[woody-apple]

The code generated for the case when a non-nullable value was saved via saveAs
and then a nullable value was being compared to it did not compile, because we
would try to do .IsNull() and .Value() on the non-nullable saved value.

The changes here check whether the saved value is actually nullable and generate
code accordingly, instead of assuming that if we're comparing a nullable to
something the something must also be nullable.

Problem

See above. This came up in #21361

Change overview

See above.

Testing

Verified that regenerating #21361 with this change makes it generate correct code.

[github-actions]

PR #21516: Size comparison from 7571349 to 39cff88

Increases (1 build for esp32)

platform	target	config	section	7571349	39cff88	change	% change
esp32	all-clusters-app	c3devkit	(read only)	1024402	1024406	4	0.0
			.flash.text	1024402	1024406	4	0.0

Decreases (1 build for telink)

platform	target	config	section	7571349	39cff88	change	% change
telink	lighting-app	tlsr9518adk80d	text	584806	584802	-4	-0.0

Full report (43 builds for bl602, cc13x2_26x2, cyw30739, efr32, esp32, k32w, linux, mbed, nrfconnect, p6, telink)

platform	target	config	section	7571349	39cff88	change	% change
bl602	lighting-app	bl602	(read/write)	1382266	1382266	0	0.0
			.bss	117626	117626	0	0.0
			.data	4480	4480	0	0.0
			.text	1052380	1052380	0	0.0
		bl602+rpc	(read/write)	1427698	1427698	0	0.0
			.bss	125066	125066	0	0.0
			.data	4600	4600	0	0.0
			.text	1084072	1084072	0	0.0
cc13x2_26x2	all-clusters-app	LP_CC2652R7	(read only)	669707	669707	0	0.0
			(read/write)	181676	181676	0	0.0
			.bss	74276	74276	0	0.0
			.data	3372	3372	0	0.0
			.rodata	88467	88467	0	0.0
			.text	580924	580924	0	0.0
	all-clusters-minimal-app	LP_CC2652R7	(read only)	635227	635227	0	0.0
			(read/write)	157844	157844	0	0.0
			.bss	73556	73556	0	0.0
			.data	3372	3372	0	0.0
			.rodata	77691	77691	0	0.0
			.text	557212	557212	0	0.0
	lock-ftd	LP_CC2652R7	(read only)	672567	672567	0	0.0
			(read/write)	169000	169000	0	0.0
			.bss	71348	71348	0	0.0
			.data	3296	3296	0	0.0
			.rodata	76535	76535	0	0.0
			.text	595552	595552	0	0.0
	lock-mtd	LP_CC2652R7	(read only)	655139	655139	0	0.0
			(read/write)	182116	182116	0	0.0
			.bss	67036	67036	0	0.0
			.data	3296	3296	0	0.0
			.rodata	101531	101531	0	0.0
			.text	553128	553128	0	0.0
	pump-app	LP_CC2652R7	(read only)	681055	681055	0	0.0
			(read/write)	161320	161320	0	0.0
			.bss	71388	71388	0	0.0
			.data	3296	3296	0	0.0
			.rodata	88919	88919	0	0.0
			.text	591652	591652	0	0.0
	pump-controller-app	LP_CC2652R7	(read only)	666631	666631	0	0.0
			(read/write)	175880	175880	0	0.0
			.bss	71524	71524	0	0.0
			.data	3292	3292	0	0.0
			.rodata	84743	84743	0	0.0
			.text	581408	581408	0	0.0
	shell	LP_CC2652R7	(read only)	662414	662414	0	0.0
			(read/write)	184488	184488	0	0.0
			.bss	76596	76596	0	0.0
			.data	3376	3376	0	0.0
			.rodata	85446	85446	0	0.0
			.text	576652	576652	0	0.0
cyw30739	light	cyw930739m2evb_01	(read/write)	583742	583742	0	0.0
			.app_xip_area	460696	460696	0	0.0
			.bss	65632	65632	0	0.0
			.data	744	744	0	0.0
			.rodata	0	0	0	0.0
			.text	112	112	0	0.0
	lock	cyw930739m2evb_01	(read/write)	589998	589998	0	0.0
			.app_xip_area	462200	462200	0	0.0
			.bss	70384	70384	0	0.0
			.data	748	748	0	0.0
			.rodata	0	0	0	0.0
			.text	112	112	0	0.0
	ota-requestor-no-progress-logging	cyw930739m2evb_01	(read/write)	589458	589458	0	0.0
			.app_xip_area	467220	467220	0	0.0
			.bss	64880	64880	0	0.0
			.data	688	688	0	0.0
			.rodata	0	0	0	0.0
			.text	112	112	0	0.0
efr32	lighting-app	BRD4161A	(read/write)	1088960	1088960	0	0.0
			.bss	133268	133268	0	0.0
			.data	2064	2064	0	0.0
			.text	953608	953608	0	0.0
		BRD4161A+rpc	(read/write)	1143300	1143300	0	0.0
			.bss	149948	149948	0	0.0
			.data	2276	2276	0	0.0
			.text	991056	991056	0	0.0
		BRD4161A+rs911x	(read/write)	974256	974256	0	0.0
			.bss	161744	161744	0	0.0
			.data	2048	2048	0	0.0
			.text	810444	810444	0	0.0
	lock-app	BRD4161A+wf200	(read/write)	1130096	1130096	0	0.0
			.bss	144400	144400	0	0.0
			.data	2056	2056	0	0.0
			.text	983620	983620	0	0.0
	window-app	BRD4161A	(read/write)	1082252	1082252	0	0.0
			.bss	134748	134748	0	0.0
			.data	2092	2092	0	0.0
			.text	945388	945388	0	0.0
esp32	all-clusters-app	c3devkit	(read only)	1024402	1024406	4	0.0
			(read/write)	1487042	1487042	0	0.0
			.dram0.bss	70336	70336	0	0.0
			.dram0.data	14600	14600	0	0.0
			.flash.rodata	216672	216672	0	0.0
			.flash.text	1024402	1024406	4	0.0
			.iram0.text	62902	62902	0	0.0
		m5stack	(read only)	1077855	1077855	0	0.0
			(read/write)	489064	489064	0	0.0
			.dram0.bss	75840	75840	0	0.0
			.dram0.data	34144	34144	0	0.0
			.flash.rodata	247084	247084	0	0.0
			.flash.text	1072471	1072471	0	0.0
			.iram0.text	123267	123267	0	0.0
k32w	light	k32w0+release	(read/write)	643352	643352	0	0.0
			.bss	69720	69720	0	0.0
			.data	2044	2044	0	0.0
			.text	568860	568860	0	0.0
	lock	k32w0+release	(read/write)	701496	701496	0	0.0
			.bss	70184	70184	0	0.0
			.data	2052	2052	0	0.0
			.text	626532	626532	0	0.0
linux	all-clusters-app	debug	(read only)	3012569	3012569	0	0.0
			(read/write)	155752	155752	0	0.0
			.bss	61952	61952	0	0.0
			.data	2064	2064	0	0.0
			.data.rel.ro	85384	85384	0	0.0
			.dynamic	608	608	0	0.0
			.got	4568	4568	0	0.0
			.init	27	27	0	0.0
			.init_array	1152	1152	0	0.0
			.rodata	271115	271115	0	0.0
			.text	2562594	2562594	0	0.0
	all-clusters-minimal-app	debug	(read only)	2854857	2854857	0	0.0
			(read/write)	147488	147488	0	0.0
			.bss	61152	61152	0	0.0
			.data	2064	2064	0	0.0
			.data.rel.ro	77992	77992	0	0.0
			.dynamic	608	608	0	0.0
			.got	4488	4488	0	0.0
			.init	27	27	0	0.0
			.init_array	1144	1144	0	0.0
			.rodata	271307	271307	0	0.0
			.text	2407298	2407298	0	0.0
	bridge-app	debug+rpc	(read only)	2360265	2360265	0	0.0
			(read/write)	127584	127584	0	0.0
			.bss	50592	50592	0	0.0
			.data	3600	3600	0	0.0
			.data.rel.ro	67544	67544	0	0.0
			.dynamic	608	608	0	0.0
			.got	4392	4392	0	0.0
			.init	27	27	0	0.0
			.init_array	824	824	0	0.0
			.rodata	202152	202152	0	0.0
			.text	1995106	1995106	0	0.0
	chip-tool	debug	(read only)	10484785	10484785	0	0.0
			(read/write)	629312	629312	0	0.0
			.bss	24856	24856	0	0.0
			.data	3266	3266	0	0.0
			.data.rel.ro	594688	594688	0	0.0
			.dynamic	608	608	0	0.0
			.got	5088	5088	0	0.0
			.init	27	27	0	0.0
			.init_array	768	768	0	0.0
			.rodata	538165	538165	0	0.0
			.text	8499172	8499172	0	0.0
	chip-tool-ipv6only	arm64	(read only)	9889644	9889644	0	0.0
			(read/write)	676865	676865	0	0.0
			.bss	32897	32897	0	0.0
			.data	3272	3272	0	0.0
			.data.rel.ro	622200	622200	0	0.0
			.dynamic	560	560	0	0.0
			.got	13536	13536	0	0.0
			.init	24	24	0	0.0
			.init_array	192	192	0	0.0
			.rodata	470140	470140	0	0.0
			.text	7841492	7841492	0	0.0
	lighting-app	debug+rpc	(read only)	2582609	2582609	0	0.0
			(read/write)	130232	130232	0	0.0
			.bss	49728	49728	0	0.0
			.data	2096	2096	0	0.0
			.data.rel.ro	72456	72456	0	0.0
			.dynamic	608	608	0	0.0
			.got	4392	4392	0	0.0
			.init	27	27	0	0.0
			.init_array	912	912	0	0.0
			.rodata	217744	217744	0	0.0
			.text	2193794	2193794	0	0.0
	lock-app	debug	(read only)	2571433	2571433	0	0.0
			(read/write)	125568	125568	0	0.0
			.bss	48256	48256	0	0.0
			.data	1712	1712	0	0.0
			.data.rel.ro	69592	69592	0	0.0
			.dynamic	608	608	0	0.0
			.got	4464	4464	0	0.0
			.init	27	27	0	0.0
			.init_array	888	888	0	0.0
			.rodata	235376	235376	0	0.0
			.text	2169042	2169042	0	0.0
	ota-provider-app	debug	(read only)	2351297	2351297	0	0.0
			(read/write)	119048	119048	0	0.0
			.bss	47808	47808	0	0.0
			.data	1936	1936	0	0.0
			.data.rel.ro	63416	63416	0	0.0
			.dynamic	608	608	0	0.0
			.got	4488	4488	0	0.0
			.init	27	27	0	0.0
			.init_array	768	768	0	0.0
			.rodata	208312	208312	0	0.0
			.text	1979106	1979106	0	0.0
	ota-requestor-app	debug	(read only)	2471873	2471873	0	0.0
			(read/write)	126440	126440	0	0.0
			.bss	50176	50176	0	0.0
			.data	2240	2240	0	0.0
			.data.rel.ro	68072	68072	0	0.0
			.dynamic	608	608	0	0.0
			.got	4480	4480	0	0.0
			.init	27	27	0	0.0
			.init_array	832	832	0	0.0
			.rodata	211840	211840	0	0.0
			.text	2087538	2087538	0	0.0
	shell	debug	(read only)	2584345	2584345	0	0.0
			(read/write)	141872	141872	0	0.0
			.bss	57800	57800	0	0.0
			.data	1264	1264	0	0.0
			.data.rel.ro	77008	77008	0	0.0
			.dynamic	608	608	0	0.0
			.got	4136	4136	0	0.0
			.init	27	27	0	0.0
			.init_array	1024	1024	0	0.0
			.rodata	232338	232338	0	0.0
			.text	2193778	2193778	0	0.0
	thermostat-no-ble	arm64	(read only)	2349420	2349420	0	0.0
			(read/write)	141761	141761	0	0.0
			.bss	55329	55329	0	0.0
			.data	1672	1672	0	0.0
			.data.rel.ro	75976	75976	0	0.0
			.dynamic	560	560	0	0.0
			.got	5016	5016	0	0.0
			.init	24	24	0	0.0
			.init_array	408	408	0	0.0
			.rodata	139316	139316	0	0.0
			.text	1972592	1972592	0	0.0
	tv-app	debug	(read only)	3136329	3136329	0	0.0
			(read/write)	257520	257520	0	0.0
			.bss	167288	167288	0	0.0
			.data	4736	4736	0	0.0
			.data.rel.ro	78960	78960	0	0.0
			.dynamic	608	608	0	0.0
			.got	4848	4848	0	0.0
			.init	27	27	0	0.0
			.init_array	1072	1072	0	0.0
			.rodata	255144	255144	0	0.0
			.text	2691922	2691922	0	0.0
	tv-casting-app	debug	(read only)	5388945	5388945	0	0.0
			(read/write)	158728	158728	0	0.0
			.bss	51384	51384	0	0.0
			.data	2432	2432	0	0.0
			.data.rel.ro	98504	98504	0	0.0
			.dynamic	608	608	0	0.0
			.got	4736	4736	0	0.0
			.init	27	27	0	0.0
			.init_array	1032	1032	0	0.0
			.rodata	339185	339185	0	0.0
			.text	4782466	4782466	0	0.0
mbed	lock-app	CY8CPROTO_062_4343W+release	(read only)	6224	6224	0	0.0
			(read/write)	2453224	2453224	0	0.0
			.bss	214548	214548	0	0.0
			.data	5872	5872	0	0.0
			.text	1415868	1415868	0	0.0
nrfconnect	all-clusters-app	nrf52840dk_nrf52840	(read/write)	1180919	1180919	0	0.0
			bss	143224	143224	0	0.0
			rodata	143344	143344	0	0.0
			text	815504	815504	0	0.0
	all-clusters-minimal-app	nrf52840dk_nrf52840	(read/write)	1160811	1160811	0	0.0
			bss	142460	142460	0	0.0
			rodata	134876	134876	0	0.0
			text	804652	804652	0	0.0
p6	all-clusters-app	default	(read only)	881528	881528	0	0.0
			(read/write)	1689268	1689268	0	0.0
			.bss	149168	149168	0	0.0
			.data	2648	2648	0	0.0
			.text	1529064	1529064	0	0.0
	all-clusters-minimal-app	default	(read only)	882248	882248	0	0.0
			(read/write)	1633300	1633300	0	0.0
			.bss	148448	148448	0	0.0
			.data	2648	2648	0	0.0
			.text	1473816	1473816	0	0.0
	light-app	default	(read only)	890568	890568	0	0.0
			(read/write)	1553348	1553348	0	0.0
			.bss	140336	140336	0	0.0
			.data	2440	2440	0	0.0
			.text	1402184	1402184	0	0.0
	lock-app	default	(read only)	886072	886072	0	0.0
			(read/write)	1591988	1591988	0	0.0
			.bss	144816	144816	0	0.0
			.data	2456	2456	0	0.0
			.text	1436328	1436328	0	0.0
telink	light-switch-app	tlsr9518adk80d	(read/write)	800512	800512	0	0.0
			bss	70808	70808	0	0.0
			noinit	40416	40416	0	0.0
			text	567942	567942	0	0.0
	lighting-app	tlsr9518adk80d	(read/write)	820928	820928	0	0.0
			bss	71652	71652	0	0.0
			noinit	40416	40416	0	0.0
			text	584806	584802	-4	-0.0