[benchmark] Janitor Duty: Lexicon Legacy

[palimondo]

This PR follows-up #20861, #21413 and #21516. It's a next batch of benchmark clean-up to enable robust performance measurements by adjusting workloads to run in reasonable time (< 1000 μs), minimizing the accumulated error. To maintain long-term performance tracking, it applies legacy factor where necessary.

This one's about Dicts...

[palimondo]

@swift-ci please benchmark

[palimondo]

@swift-ci please smoke test

[palimondo]

@swift-ci please benchmark

[swift-ci]

Build comment file:

Performance: -O

TEST	OLD	NEW	DELTA	RATIO
Regression
DataAppendDataLargeToLarge	37600	51400	+36.7%	0.73x (?)
ObjectiveCBridgeStubToNSDate2	1236	1338	+8.3%	0.92x (?)
Improvement
ObjectiveCBridgeStubFromArrayOfNSString2	3471	3219	-7.3%	1.08x (?)

Performance: -Osize

TEST	OLD	NEW	DELTA	RATIO
Improvement
DataAppendDataLargeToLarge	51400	37400	-27.2%	1.37x (?)

Code size: -Osize

TEST	OLD	NEW	DELTA	RATIO
Improvement
DictTest2.o	9833	9721	-1.1%	1.01x

Performance: -Onone

TEST	OLD	NEW	DELTA	RATIO
Regression
ObjectiveCBridgeToNSDictionary	16551	18392	+11.1%	0.90x (?)
Improvement
DataAppendDataLargeToLarge	51400	38400	-25.3%	1.34x (?)

How to read the data

The tables contain differences in performance which are larger than 8% and differences in code size which are larger than 1%.

If you see any unexpected regressions, you should consider fixing the
regressions before you merge the PR.

Noise: Sometimes the performance results (not code size!) contain false
alarms. Unexpected regressions which are marked with '(?)' are probably noise.
If you see regressions which you cannot explain you can try to run the
benchmarks again. If regressions still show up, please consult with the
performance team (@eeckstein).

Hardware Overview

  Model Name: Mac Pro
  Model Identifier: MacPro6,1
  Processor Name: 12-Core Intel Xeon E5
  Processor Speed: 2.7 GHz
  Number of Processors: 1
  Total Number of Cores: 12
  L2 Cache (per Core): 256 KB
  L3 Cache: 30 MB
  Memory: 64 GB

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[palimondo]

@swift-ci please smoke test

[palimondo]

@eeckstein Please review 🙏 (Today just a short one… I'm burnt out in this 🚽)

[palimondo]

Thank you Erik!