Avoid unnecessary slice allocations

[turbolent]

Description

Do not unnecessarily allocate empty slices.

---

• 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]

Codecov Report

Merging #2191 (94be3f1) into master (29fd837) will decrease coverage by 0.01%.
The diff coverage is 82.61%.

@@            Coverage Diff             @@
##           master    #2191      +/-   ##
==========================================
- Coverage   77.60%   77.58%   -0.02%     
==========================================
  Files         309      309              
  Lines       65289    65406     +117     
==========================================
+ Hits        50666    50747      +81     
- Misses      12852    12880      +28     
- Partials     1771     1779       +8     

Flag	Coverage Δ
unittests	77.58% <82.61%> (-0.02%)	⬇️

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

Impacted Files	Coverage Δ
runtime/interpreter/decode.go	46.28% <24.13%> (+0.08%)	⬆️
runtime/interpreter/statictype.go	78.35% <28.35%> (-4.77%)	⬇️
runtime/interpreter/interpreter_invocation.go	91.66% <75.67%> (+0.40%)	⬆️
runtime/interpreter/interpreter.go	89.34% <97.05%> (+0.05%)	⬆️
runtime/interpreter/conversion.go	92.75% <100.00%> (+0.95%)	⬆️
runtime/interpreter/interpreter_expression.go	86.77% <100.00%> (+0.22%)	⬆️
runtime/sema/check_array_expression.go	100.00% <100.00%> (ø)
runtime/sema/check_dictionary_expression.go	100.00% <100.00%> (ø)
runtime/sema/check_invocation_expression.go	98.21% <100.00%> (+0.03%)	⬆️
runtime/sema/check_transaction_declaration.go	84.61% <100.00%> (+0.32%)	⬆️
... and 14 more

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[github-actions]

Cadence Benchstat comparison

This branch with compared with the base branch onflow:master commit 29fd837
The command for i in {1..N}; do go test ./... -run=XXX -bench=. -benchmem -shuffle=on; done was used.
Bench tests were run a total of 7 times on each branch.

Collapsed results for better readability

	old.txt	new.txt
	time/op		delta
CheckContractInterfaceFungibleTokenConformance-2	109µs ± 0%	108µs ± 0%	−0.88%	(p=0.002 n=6+6)
ContractInterfaceFungibleToken-2	37.5µs ± 1%	37.4µs ± 1%	~	(p=0.421 n=6+7)
InterpretRecursionFib-2	2.45ms ± 2%	2.44ms ± 1%	~	(p=0.318 n=7+7)
NewInterpreter/new_interpreter-2	1.09µs ± 1%	1.08µs ± 0%	−0.83%	(p=0.002 n=7+7)
NewInterpreter/new_sub-interpreter-2	571ns ± 0%	570ns ± 1%	~	(p=0.475 n=7+7)
ParseArray-2	7.50ms ± 1%	7.68ms ± 4%	~	(p=0.053 n=7+7)
ParseDeploy/byte_array-2	11.5ms ± 3%	11.5ms ± 5%	~	(p=1.000 n=7+7)
ParseDeploy/decode_hex-2	1.21ms ± 1%	1.20ms ± 1%	~	(p=0.366 n=6+7)
ParseFungibleToken/With_memory_metering-2	181µs ± 0%	184µs ± 2%	+1.55%	(p=0.022 n=6+7)
ParseFungibleToken/Without_memory_metering-2	141µs ± 0%	143µs ± 3%	~	(p=0.053 n=7+7)
ParseInfix-2	7.19µs ± 7%	6.99µs ± 1%	~	(p=0.628 n=7+6)
QualifiedIdentifierCreation/One_level-2	2.41ns ± 0%	2.41ns ± 0%	−0.07%	(p=0.045 n=6+7)
QualifiedIdentifierCreation/Three_levels-2	117ns ± 1%	115ns ± 1%	−1.57%	(p=0.001 n=7+6)
RuntimeFungibleTokenTransfer-2	576µs ±24%	493µs ±29%	~	(p=0.073 n=7+7)
RuntimeResourceDictionaryValues-2	5.05ms ± 1%	5.07ms ± 0%	~	(p=0.073 n=7+6)
RuntimeScriptNoop-2	16.4µs ±29%	17.3µs ±24%	~	(p=0.383 n=7+7)
SuperTypeInference/arrays-2	292ns ± 4%	282ns ± 1%	−3.23%	(p=0.001 n=7+6)
SuperTypeInference/composites-2	130ns ± 0%	130ns ± 0%	~	(p=0.600 n=6+6)
SuperTypeInference/integers-2	92.7ns ± 0%	90.5ns ± 0%	−2.45%	(p=0.001 n=7+7)
ValueIsSubtypeOfSemaType-2	86.2ns ± 3%	86.9ns ± 1%	~	(p=0.245 n=7+7)
	alloc/op		delta
CheckContractInterfaceFungibleTokenConformance-2	48.8kB ± 0%	48.7kB ± 0%	−0.10%	(p=0.001 n=7+7)
ContractInterfaceFungibleToken-2	22.9kB ± 0%	22.9kB ± 0%	~	(all equal)
InterpretRecursionFib-2	1.00MB ± 0%	1.00MB ± 0%	~	(p=0.636 n=5+7)
NewInterpreter/new_interpreter-2	768B ± 0%	768B ± 0%	~	(all equal)
NewInterpreter/new_sub-interpreter-2	200B ± 0%	200B ± 0%	~	(all equal)
ParseArray-2	2.70MB ± 2%	2.78MB ± 5%	~	(p=0.165 n=7+7)
ParseDeploy/byte_array-2	4.18MB ± 2%	4.09MB ± 0%	~	(p=0.343 n=7+5)
ParseDeploy/decode_hex-2	214kB ± 0%	214kB ± 0%	~	(p=0.106 n=6+7)
ParseFungibleToken/With_memory_metering-2	29.2kB ± 0%	29.2kB ± 0%	~	(p=0.286 n=7+7)
ParseFungibleToken/Without_memory_metering-2	29.2kB ± 0%	29.2kB ± 0%	~	(p=0.580 n=7+7)
ParseInfix-2	1.92kB ± 0%	1.92kB ± 0%	~	(p=0.103 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)
RuntimeFungibleTokenTransfer-2	102kB ± 1%	101kB ± 0%	−0.73%	(p=0.011 n=7+7)
RuntimeResourceDictionaryValues-2	2.28MB ± 0%	2.28MB ± 0%	~	(p=0.902 n=7+7)
RuntimeScriptNoop-2	6.77kB ± 0%	6.78kB ± 1%	~	(p=0.971 n=7+7)
SuperTypeInference/arrays-2	96.0B ± 0%	96.0B ± 0%	~	(all equal)
SuperTypeInference/composites-2	0.00B	0.00B	~	(all equal)
SuperTypeInference/integers-2	0.00B	0.00B	~	(all equal)
ValueIsSubtypeOfSemaType-2	48.0B ± 0%	48.0B ± 0%	~	(all equal)
	allocs/op		delta
CheckContractInterfaceFungibleTokenConformance-2	797 ± 0%	794 ± 0%	−0.38%	(p=0.001 n=7+7)
ContractInterfaceFungibleToken-2	363 ± 0%	363 ± 0%	~	(all equal)
InterpretRecursionFib-2	18.9k ± 0%	18.9k ± 0%	~	(all equal)
NewInterpreter/new_interpreter-2	13.0 ± 0%	13.0 ± 0%	~	(all equal)
NewInterpreter/new_sub-interpreter-2	4.00 ± 0%	4.00 ± 0%	~	(all equal)
ParseArray-2	59.6k ± 0%	59.6k ± 0%	~	(p=0.245 n=6+7)
ParseDeploy/byte_array-2	89.4k ± 0%	89.4k ± 0%	~	(p=0.098 n=7+6)
ParseDeploy/decode_hex-2	64.0 ± 0%	64.0 ± 0%	~	(all equal)
ParseFungibleToken/With_memory_metering-2	779 ± 0%	779 ± 0%	~	(all equal)
ParseFungibleToken/Without_memory_metering-2	779 ± 0%	779 ± 0%	~	(all equal)
ParseInfix-2	48.0 ± 0%	48.0 ± 0%	~	(all equal)
QualifiedIdentifierCreation/One_level-2	0.00	0.00	~	(all equal)
QualifiedIdentifierCreation/Three_levels-2	2.00 ± 0%	2.00 ± 0%	~	(all equal)
RuntimeFungibleTokenTransfer-2	1.97k ± 0%	1.96k ± 0%	−0.34%	(p=0.001 n=7+7)
RuntimeResourceDictionaryValues-2	36.9k ± 0%	36.9k ± 0%	−0.01%	(p=0.001 n=7+7)
RuntimeScriptNoop-2	98.0 ± 0%	98.0 ± 0%	~	(all equal)
SuperTypeInference/arrays-2	3.00 ± 0%	3.00 ± 0%	~	(all equal)
SuperTypeInference/composites-2	0.00	0.00	~	(all equal)
SuperTypeInference/integers-2	0.00	0.00	~	(all equal)
ValueIsSubtypeOfSemaType-2	1.00 ± 0%	1.00 ± 0%	~	(all equal)