[LS] Remove caching of checkers for imported programs

[devbugging]

Closes #1571

Description

When LS is resolving the imports it uses a cached checker which doesn't include any changes to the imported program resulting in the current program not seeing those changes in diagnostics / code completions. This PR makes sure the checker is initialized every time, which arguably can be expensive but it's meant to be a quick patch on the blocking problem in production, a better way would be to have a "reversed" dependency tree and figure out which dependencies actually change and not just do a new re-init every time, this is been documented in an issue for future #1570.

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• 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

[github-actions]

Cadence Benchstat comparison

This branch with compared with the base branch onflow:master commit 07c27c2
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
ParseInfix-2	8.28µs ± 1%	8.37µs ± 1%	+1.11%	(p=0.004 n=7+7)
ParseFungibleToken-2	180µs ± 1%	182µs ± 0%	+0.74%	(p=0.005 n=7+6)
RuntimeFungibleTokenTransfer-2	1.13ms ±29%	1.19ms ±24%	~	(p=0.902 n=7+7)
ParseDeploy/byte_array-2	19.5ms ± 2%	19.6ms ± 3%	~	(p=0.318 n=7+7)
ParseDeploy/decode_hex-2	1.15ms ± 1%	1.16ms ± 2%	~	(p=0.181 n=6+7)
ParseArray-2	12.2ms ± 3%	12.4ms ± 3%	~	(p=0.456 n=7+7)
QualifiedIdentifierCreation/One_level-2	2.34ns ± 0%	2.34ns ± 0%	~	(p=0.219 n=6+7)
QualifiedIdentifierCreation/Three_levels-2	138ns ± 1%	139ns ± 1%	~	(p=0.273 n=7+7)
CheckContractInterfaceFungibleTokenConformance-2	131µs ± 1%	131µs ± 1%	~	(p=0.710 n=7+7)
ContractInterfaceFungibleToken-2	39.0µs ± 1%	39.1µs ± 1%	~	(p=0.295 n=7+6)
NewInterpreter/new_interpreter-2	1.12µs ± 1%	1.13µs ± 1%	~	(p=0.134 n=7+7)
NewInterpreter/new_sub-interpreter-2	2.20µs ± 0%	2.20µs ± 1%	~	(p=0.646 n=6+7)
InterpretRecursionFib-2	2.79ms ± 1%	2.69ms ± 0%	−3.60%	(p=0.001 n=7+6)
RuntimeResourceDictionaryValues-2	13.4ms ± 2%	6.3ms ± 4%	−52.98%	(p=0.001 n=7+7)
	alloc/op		delta
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=0.462 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)
RuntimeFungibleTokenTransfer-2	273kB ± 0%	273kB ± 0%	−0.10%	(p=0.001 n=7+7)
InterpretRecursionFib-2	1.26MB ± 0%	1.14MB ± 0%	−9.30%	(p=0.000 n=6+7)
RuntimeResourceDictionaryValues-2	4.05MB ± 0%	2.25MB ± 0%	−44.36%	(p=0.001 n=7+7)
	allocs/op		delta
RuntimeFungibleTokenTransfer-2	4.54k ± 0%	4.58k ± 0%	+1.00%	(p=0.001 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)
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)
InterpretRecursionFib-2	26.2k ± 0%	23.8k ± 0%	−9.30%	(p=0.001 n=7+7)
RuntimeResourceDictionaryValues-2	102k ± 0%	38k ± 0%	−63.03%	(p=0.001 n=7+7)

[codecov]

Codecov Report

Merging #1572 (c96eeb5) into master (c63336c) will decrease coverage by 0.03%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1572      +/-   ##
==========================================
- Coverage   74.69%   74.65%   -0.04%     
==========================================
  Files         289      288       -1     
  Lines       55625    55364     -261     
==========================================
- Hits        41549    41332     -217     
+ Misses      12581    12535      -46     
- Partials     1495     1497       +2     

Flag	Coverage Δ
unittests	74.65% <ø> (-0.04%)	⬇️

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

Impacted Files	Coverage Δ
runtime/interpreter/function.go	52.71% <0.00%> (-4.54%)	⬇️
runtime/interpreter/simplecompositevalue.go	59.63% <0.00%> (-3.92%)	⬇️
runtime/sema/simple_type.go	92.30% <0.00%> (-3.85%)	⬇️
runtime/interpreter/accountkeys.go	77.27% <0.00%> (-0.99%)	⬇️
runtime/convertValues.go	77.95% <0.00%> (-0.88%)	⬇️
runtime/interpreter/accountcontracts.go	81.13% <0.00%> (-0.69%)	⬇️
runtime/interpreter/block.go	90.00% <0.00%> (-0.48%)	⬇️
runtime/interpreter/value.go	63.63% <0.00%> (-0.37%)	⬇️
runtime/stdlib/rlp.go	86.00% <0.00%> (-0.14%)	⬇️
runtime/interpreter/account.go	92.48% <0.00%> (-0.12%)	⬇️
... and 20 more

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