Speed up bootstrap __build_class__ a little bit

[tekknolagi]

Since we're iterating over the layouts table one by one, and the layouts table will always be at least LayoutId::kLastBuiltinId layouts long, use Runtime::layoutAt instead of Runtime::layoutAtSafe, which does a bunch of checks. This search is still linear and kind of long, though.

[github-actions]

Summary

Metric	Average	Best	Worst	Notes
cg_instructions	-0.0%	loadproperty -0.1%	pyflate -0.0%	typically < 0.2% noise

Base vs. New

benchmark	cg_instructions
2to3	-0.0%
bench_base64	-0.0%
bench_pickle	-0.0%
deltablue	-0.0%
fannkuch	-0.0%
go	-0.0%
loadproperty	-0.1%
nbody	-0.0%
nqueens	-0.0%
pyflate	-0.0%
pystone	-0.0%
richards	-0.0%

CPython vs New

benchmark	cg_instructions
2to3	-4.9%
bench_base64	-37.4%
bench_pickle	-18.5%
deltablue	-64.3%
fannkuch	0.5%
go	-63.4%
loadproperty	-74.6%
nbody	23.5%
nqueens	45.8%
pyflate	-30.5%
pystone	-71.1%
richards	-79.6%

Base

benchmark	cg_instructions
2to3	2,437,961,900
bench_base64	3,016,851,640
bench_pickle	3,377,761,245
deltablue	1,472,154,711
fannkuch	5,623,193,634
go	1,927,823,470
loadproperty	443,757,304
nbody	9,628,670,603
nqueens	3,227,848,546
pyflate	10,052,583,375
pystone	1,150,087,213
richards	985,751,874

New

benchmark	cg_instructions
2to3	2,437,759,495
bench_base64	3,016,639,065
bench_pickle	3,377,448,086
deltablue	1,471,938,135
fannkuch	5,622,975,914
go	1,927,591,646
loadproperty	443,533,351
nbody	9,628,444,593
nqueens	3,227,622,501
pyflate	10,052,353,183
pystone	1,149,852,950
richards	985,517,204

CPython

benchmark	cg_instructions
2to3	2,563,386,938
bench_base64	4,817,675,046
bench_pickle	4,144,883,649
deltablue	4,118,306,138
fannkuch	5,594,116,616
go	5,264,496,480
loadproperty	1,747,782,927
nbody	7,793,828,860
nqueens	2,213,992,826
pyflate	14,465,369,585
pystone	3,981,020,686
richards	4,820,465,409

[github-actions]

Summary

Metric	Average	Best	Worst	Notes
cg_instructions	-0.0%	loadproperty -0.1%	pyflate -0.0%	typically < 0.2% noise

Base vs. New

benchmark	cg_instructions
2to3	-0.0%
bench_base64	-0.0%
bench_pickle	-0.0%
deltablue	-0.0%
fannkuch	-0.0%
go	-0.0%
loadproperty	-0.1%
nbody	-0.0%
nqueens	-0.0%
pyflate	-0.0%
pystone	-0.0%
richards	-0.0%

CPython vs New

benchmark	cg_instructions
2to3	-4.9%
bench_base64	-37.4%
bench_pickle	-18.5%
deltablue	-64.3%
fannkuch	0.5%
go	-63.4%
loadproperty	-74.6%
nbody	23.5%
nqueens	45.8%
pyflate	-30.5%
pystone	-71.1%
richards	-79.6%

Base

benchmark	cg_instructions
2to3	2,437,961,900
bench_base64	3,016,851,640
bench_pickle	3,377,761,245
deltablue	1,472,154,711
fannkuch	5,623,193,634
go	1,927,823,470
loadproperty	443,757,304
nbody	9,628,670,603
nqueens	3,227,848,546
pyflate	10,052,583,375
pystone	1,150,087,213
richards	985,751,874

New

benchmark	cg_instructions
2to3	2,437,727,592
bench_base64	3,016,607,162
bench_pickle	3,377,416,183
deltablue	1,471,906,232
fannkuch	5,622,944,011
go	1,927,559,743
loadproperty	443,501,448
nbody	9,628,412,690
nqueens	3,227,590,598
pyflate	10,052,321,280
pystone	1,149,821,047
richards	985,485,301

CPython

benchmark	cg_instructions
2to3	2,563,386,945
bench_base64	4,817,675,046
bench_pickle	4,144,883,649
deltablue	4,118,306,138
fannkuch	5,594,116,623
go	5,264,496,480
loadproperty	1,747,782,934
nbody	7,793,830,178
nqueens	2,213,992,833
pyflate	14,465,369,585
pystone	3,981,020,686
richards	4,820,465,409