Box optional-typed references to non-optional values

[turbolent]

Description

While investigating #1539 I noticed that #1303 was not properly handling the case of taking a reference where the value is non-optional and the borrowed type is optional. In that case the result must be boxed properly.

Also, add interpreter tests for all cases of taking references to optionals.

---

• Targeted PR against master branch
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work
• Code follows the standards mentioned here
• Updated relevant documentation
• Re-reviewed Files changed in the Github PR explorer
• Added appropriate labels

[codecov-commenter]

Codecov Report

Merging #1542 (968d955) into master (c63336c) will decrease coverage by 0.00%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1542      +/-   ##
==========================================
- Coverage   74.69%   74.69%   -0.01%     
==========================================
  Files         289      289              
  Lines       55625    55640      +15     
==========================================
+ Hits        41549    41560      +11     
- Misses      12581    12585       +4     
  Partials     1495     1495              

Flag	Coverage Δ
unittests	74.69% <100.00%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
runtime/interpreter/interpreter_expression.go	84.24% <100.00%> (+0.33%)	⬆️
runtime/sema/simple_type.go	92.30% <0.00%> (-3.85%)	⬇️
runtime/interpreter/storage.go	71.42% <0.00%> (-1.37%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update c63336c...968d955. Read the comment docs.

[github-actions]

Cadence Benchstat comparison

This branch with compared with the base branch onflow:master commit c63336c
The command for i in {1..N}; do go test ./... -run=XXX -bench=. -shuffle=on; done was used.
Bench tests were run a total of 7 times on each branch.

Results

	old.txt	new.txt
	time/op		delta
RuntimeResourceDictionaryValues-2	15.9ms ± 6%	15.6ms ± 3%	~	(p=0.295 n=7+6)
RuntimeFungibleTokenTransfer-2	1.47ms ±24%	1.37ms ±33%	~	(p=0.456 n=7+7)
ParseDeploy/byte_array-2	22.4ms ± 9%	22.4ms ± 9%	~	(p=0.902 n=7+7)
ParseDeploy/decode_hex-2	1.42ms ± 6%	1.41ms ± 6%	~	(p=0.710 n=7+7)
ParseFungibleToken-2	219µs ± 5%	219µs ± 5%	~	(p=0.710 n=7+7)
ParseArray-2	14.4ms ± 6%	14.5ms ± 6%	~	(p=0.456 n=7+7)
ParseInfix-2	9.48µs ± 6%	9.58µs ± 7%	~	(p=0.620 n=7+7)
QualifiedIdentifierCreation/One_level-2	3.23ns ± 6%	3.23ns ± 7%	~	(p=0.973 n=7+7)
QualifiedIdentifierCreation/Three_levels-2	168ns ± 6%	170ns ± 9%	~	(p=0.966 n=7+7)
CheckContractInterfaceFungibleTokenConformance-2	167µs ± 5%	165µs ± 4%	~	(p=0.731 n=7+6)
ContractInterfaceFungibleToken-2	47.3µs ± 6%	46.8µs ± 5%	~	(p=0.620 n=7+7)
InterpretRecursionFib-2	3.11ms ± 1%	3.11ms ± 3%	~	(p=0.628 n=6+7)
NewInterpreter/new_interpreter-2	1.30µs ± 4%	1.31µs ± 4%	~	(p=0.535 n=7+7)
NewInterpreter/new_sub-interpreter-2	2.52µs ± 5%	2.49µs ± 4%	~	(p=0.710 n=7+7)
	alloc/op		delta
RuntimeResourceDictionaryValues-2	4.05MB ± 0%	4.05MB ± 0%	~	(p=0.073 n=7+7)
RuntimeFungibleTokenTransfer-2	273kB ± 0%	273kB ± 0%	~	(p=0.365 n=7+7)
QualifiedIdentifierCreation/One_level-2	0.00B	0.00B	~	(all equal)
QualifiedIdentifierCreation/Three_levels-2	64.0B ± 0%	64.0B ± 0%	~	(all equal)
CheckContractInterfaceFungibleTokenConformance-2	66.2kB ± 0%	66.2kB ± 0%	~	(all equal)
ContractInterfaceFungibleToken-2	26.6kB ± 0%	26.6kB ± 0%	~	(p=0.192 n=7+7)
InterpretRecursionFib-2	1.26MB ± 0%	1.26MB ± 0%	~	(p=0.988 n=7+7)
NewInterpreter/new_interpreter-2	848B ± 0%	848B ± 0%	~	(all equal)
NewInterpreter/new_sub-interpreter-2	1.34kB ± 0%	1.34kB ± 0%	~	(all equal)
	allocs/op		delta
RuntimeResourceDictionaryValues-2	102k ± 0%	102k ± 0%	~	(p=0.073 n=7+7)
RuntimeFungibleTokenTransfer-2	4.54k ± 0%	4.54k ± 0%	~	(p=1.000 n=7+7)
QualifiedIdentifierCreation/One_level-2	0.00	0.00	~	(all equal)
QualifiedIdentifierCreation/Three_levels-2	2.00 ± 0%	2.00 ± 0%	~	(all equal)
CheckContractInterfaceFungibleTokenConformance-2	1.07k ± 0%	1.07k ± 0%	~	(all equal)
ContractInterfaceFungibleToken-2	458 ± 0%	458 ± 0%	~	(all equal)
InterpretRecursionFib-2	26.2k ± 0%	26.2k ± 0%	~	(all equal)
NewInterpreter/new_interpreter-2	13.0 ± 0%	13.0 ± 0%	~	(all equal)
NewInterpreter/new_sub-interpreter-2	40.0 ± 0%	40.0 ± 0%	~	(all equal)