[Gardening] Remove extra Foundation imports

[palimondo]

Remove the import of Foundation where it is not necessary for testing the ObjC interoperability.

Edit: Also import MSVCRT in Windows where the #if os(Linux) import Glibc pattern occurs.

[palimondo]

@swift-ci please benchmark

[palimondo]

@swift-ci please smoke test

[swift-ci]

Performance: -O

Regression	OLD	NEW	DELTA	RATIO
FlattenListFlatMap	4062	5313	+30.8%	0.76x (?)
FlattenListLoop	2394	2978	+24.4%	0.80x (?)

Code size: -O

Performance: -Osize

Improvement	OLD	NEW	DELTA	RATIO
ArrayAppendGenericStructs	1070	630	-41.1%	1.70x (?)

Code size: -Osize

Performance: -Onone

Improvement	OLD	NEW	DELTA	RATIO
ObjectiveCBridgeStubToNSDate2	1040	970	-6.7%	1.07x (?)

Code size: -swiftlibs

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 mini
  Model Identifier: Macmini8,1
  Processor Name: Intel Core i7
  Processor Speed: 3.2 GHz
  Number of Processors: 1
  Total Number of Cores: 6
  L2 Cache (per Core): 256 KB
  L3 Cache: 12 MB
  Memory: 64 GB

[palimondo]

Those regressions and improvements in -O and -Osize are unusually high for no changes… Similar to the other case? I wonder if these are flukes or replicable. Re-running benchmark to see.

[jrose-apple]

There are a few things that behave differently based on whether the Foundation overlays are linked into the process. :-( The set is kept pretty small but it could still be an explanation here. cc @Catfish-Man

[palimondo]

@swift-ci please benchmark

[swift-ci]

Performance: -O

Improvement	OLD	NEW	DELTA	RATIO
FlattenListFlatMap	5734	4378	-23.6%	1.31x (?)
FlattenListLoop	2868	2448	-14.6%	1.17x (?)

Code size: -O

Performance: -Osize

Regression	OLD	NEW	DELTA	RATIO
CharIteration_punctuatedJapanese_unicodeScalars	400	440	+10.0%	0.91x (?)
Improvement	OLD	NEW	DELTA	RATIO
StaticArray	2	1	-50.0%	2.00x

Code size: -Osize

Performance: -Onone

Regression	OLD	NEW	DELTA	RATIO
ObjectiveCBridgeStubFromNSDate	2980	3220	+8.1%	0.93x (?)

Code size: -swiftlibs

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 mini
  Model Identifier: Macmini8,1
  Processor Name: Intel Core i7
  Processor Speed: 3.2 GHz
  Number of Processors: 1
  Total Number of Cores: 6
  L2 Cache (per Core): 256 KB
  L3 Cache: 12 MB
  Memory: 64 GB

[eeckstein]

lgtm!
(Please address compnerd's request)

[palimondo]

@swift-ci please benchmark

[palimondo]

@swift-ci smoke test

[swift-ci]

Performance: -O

Regression	OLD	NEW	DELTA	RATIO
ObjectiveCBridgeStubFromNSStringRef	87	94	+8.0%	0.93x (?)
ObjectiveCBridgeStubFromNSDateRef	2460	2650	+7.7%	0.93x (?)
Improvement	OLD	NEW	DELTA	RATIO
FlattenListFlatMap	6339	5471	-13.7%	1.16x (?)

Code size: -O

Performance: -Osize

Regression	OLD	NEW	DELTA	RATIO
StringBuilderWithLongSubstring	950	1050	+10.5%	0.90x (?)
Improvement	OLD	NEW	DELTA	RATIO
SortLettersInPlace	406	378	-6.9%	1.07x (?)

Code size: -Osize

Performance: -Onone

Code size: -swiftlibs

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 mini
  Model Identifier: Macmini8,1
  Processor Name: Intel Core i7
  Processor Speed: 3.2 GHz
  Number of Processors: 1
  Total Number of Cores: 6
  L2 Cache (per Core): 256 KB
  L3 Cache: 12 MB
  Memory: 64 GB