[metadata prespecialization] Prespecialize common standard library types

[airspeedswift]

The standard library is already prespecializing types it uses within itself, but many commonly-used types aren't actually used by the standard library. This adds uses of these types to the std lib to force their prespecialization.

Note this list is not ABI. We can add and remove from it in each release. I generated this starter list by looking for types used by more than 1 app in a sample of a few Mac apps run on my desktop. We should eventually make resampling some representative programs to generate this list part of the Swift release process.

There are some types in this list we can't yet prespecialize (like those parameterized by non-nominal types or AnyObject) but I'm assuming those are coming so they're fine to keep in here.

[airspeedswift]

@swift-ci please test

[airspeedswift]

@swift-ci please benchmark

[nate-chandler]

LGTM! Some of these won't result in prespecialization immediately (such as those involving existentials) but as the functionality gets brought up it they will.

[swift-ci]

Performance: -O

Regression	OLD	NEW	DELTA	RATIO
EqualSubstringSubstring	23	30	+30.4%	0.77x
LessSubstringSubstring	23	30	+30.4%	0.77x
EqualStringSubstring	23	30	+30.4%	0.77x (?)
EqualSubstringSubstringGenericEquatable	23	30	+30.4%	0.77x
EqualSubstringString	23	30	+30.4%	0.77x
LessSubstringSubstringGenericComparable	23	30	+30.4%	0.77x
DistinctClassFieldAccesses	177	211	+19.2%	0.84x
StringComparison_longSharedPrefix	323	359	+11.1%	0.90x (?)
ObjectiveCBridgeStringHash	76	84	+10.5%	0.90x (?)
ObjectiveCBridgeStubToNSDate2	330	360	+9.1%	0.92x (?)
StringHasSuffixAscii	1370	1480	+8.0%	0.93x (?)
Improvement	OLD	NEW	DELTA	RATIO
Set.isSubset.Seq.Empty.Int	82	76	-7.3%	1.08x (?)

Code size: -O

Performance: -Osize

Regression	OLD	NEW	DELTA	RATIO
EqualSubstringSubstring	23	30	+30.4%	0.77x (?)
EqualStringSubstring	23	30	+30.4%	0.77x
EqualSubstringSubstringGenericEquatable	23	30	+30.4%	0.77x
EqualSubstringString	23	30	+30.4%	0.77x
LessSubstringSubstring	24	31	+29.2%	0.77x
LessSubstringSubstringGenericComparable	24	31	+29.2%	0.77x
StringComparison_longSharedPrefix	319	357	+11.9%	0.89x (?)
ObjectiveCBridgeStringHash	76	84	+10.5%	0.90x (?)
AngryPhonebook.Armenian	157	171	+8.9%	0.92x (?)
Improvement	OLD	NEW	DELTA	RATIO
Set.subtracting.Empty.Int	28	26	-7.1%	1.08x (?)

Code size: -Osize

Performance: -Onone

Regression	OLD	NEW	DELTA	RATIO
EqualSubstringSubstringGenericEquatable	27	34	+25.9%	0.79x
LessSubstringSubstringGenericComparable	27	34	+25.9%	0.79x
LessSubstringSubstring	28	35	+25.0%	0.80x
EqualSubstringSubstring	28	34	+21.4%	0.82x (?)
EqualStringSubstring	28	34	+21.4%	0.82x (?)
EqualSubstringString	28	34	+21.4%	0.82x (?)
ObjectiveCBridgeStringHash	76	84	+10.5%	0.90x (?)
AngryPhonebook.Strasse	136	150	+10.3%	0.91x (?)
Improvement	OLD	NEW	DELTA	RATIO
Set.subtracting.Seq.Empty.Int	339	279	-17.7%	1.22x
Set.isDisjoint.Empty.Int	284	234	-17.6%	1.21x
Set.subtracting.Empty.Int	72	62	-13.9%	1.16x (?)
Set.subtracting.Seq.Int.Empty	560	502	-10.4%	1.12x (?)
StringFromLongWholeSubstring	10	9	-10.0%	1.11x
Set.isStrictSubset.Seq.Int.Empty	683	618	-9.5%	1.11x (?)
Set.subtracting.Int.Empty	98	89	-9.2%	1.10x (?)
Set.isSubset.Seq.Int.Empty	685	624	-8.9%	1.10x (?)

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: 6-Core 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

[airspeedswift]

@swift-ci please test windows

[airspeedswift]

@swift-ci please test macOS

[swift-ci]

Build failed
Swift Test OS X Platform
Git Sha - 9cb7dce

[nate-chandler]

@swift-ci please clean test os x platform

[nate-chandler]

@swift-ci please clean test macOS