[stdlib][runtime] Establish Swift Stdlib/runtime version 6.3

[lorentey]

• Bump the version number of the stdlib to 6.3.
• Establish the SwiftStdlib 6.3 availability macro to mark newly introduced API. This currently resolves to placeholder (9999) OS versions, as usual.
• Establish that there is a version 6.3 of the Swift runtime in AST/RuntimeVersions.def.

[lorentey]

@swift-ci test

[lorentey]

@swift-ci test

[lorentey]

@swift-ci smoke test macOS platform

[lorentey]

@swift-ci smoke test macOS platform

[lorentey]

@swift-ci smoke test macOS platform

[lorentey]

@swift-ci smoke test

[lorentey]

@swift-ci smoke test

[lorentey]

22:04:17  FAIL: swift-package-tests :: swift-package-init-lib.md (39 of 39)
22:04:17 
 ******************** TEST 'swift-package-tests :: swift-package-init-lib.md' FAILED ********************

Sure

[lorentey]

@swift-ci smoke test

[lorentey]

Cool cool cool

[2025-05-19T19:03:50.397Z] error: could not find module '_Concurrency' for target 'arm64-apple-macos'; found: x86_64-apple-macos, at: /Users/ec2-user/jenkins/workspace/swift-PR-macos-smoke-test/branch-main/build/buildbot_incremental/swift-macosx-x86_64/lib/swift/macosx/_Concurrency.swiftmodule
[2025-05-19T19:03:50.397Z] ninja: build stopped: subcommand failed.

[lorentey]

@swift-ci smoke test macOS platform

[lorentey]

And now we can't even find the stdlib. Right.

[2025-05-20T17:27:58.166Z] error: Unable to find module dependency: 'Swift'
[2025-05-20T17:27:58.166Z] note: a dependency of main module '_RegexParser'
[2025-05-20T17:27:58.166Z] error: Unable to find module dependency: 'Swift'
[2025-05-20T17:27:58.166Z] note: a dependency of Swift module '_Concurrency': '/Users/ec2-user/jenkins/workspace/swift-PR-macos-smoke-test/branch-main/build/buildbot_incremental/swift-macosx-x86_64/lib/swift/macosx/_Concurrency.swiftmodule/arm64-apple-macos.swiftmodule'
[2025-05-20T17:27:58.166Z] note: a dependency of main module '_RegexParser'
[2025-05-20T17:27:58.166Z] ninja: build stopped: subcommand failed.
[...]
[2025-05-20T17:33:48.126Z] Building the standard library for: swift-stdlib-macosx-x86_64

[lorentey]

@swift-ci clean smoke test macOS platform

[lorentey]

Oh for heaven's sake

[2025-05-21T17:55:46.866Z] FAIL: Swift(macosx-x86_64) :: abi/macOS/x86_64/stdlib-asserts.swift (10036 of 19067)
[2025-05-21T17:55:46.866Z] ******************** TEST 'Swift(macosx-x86_64) :: abi/macOS/x86_64/stdlib-asserts.swift' FAILED ********************
[2025-05-21T17:55:46.866Z] Exit Code: 1
[2025-05-21T17:55:46.866Z] 
[2025-05-21T17:55:46.866Z] Command Output (stdout):
[2025-05-21T17:55:46.866Z] --
[2025-05-21T17:55:46.866Z] --- /Users/ec2-user/jenkins/workspace/swift-PR-macos-smoke-test/branch-main/swift/test/abi/macOS/x86_64/../../Inputs/macOS/x86_64/stdlib/baseline-asserts	2025-05-21 16:26:03
[2025-05-21T17:55:46.866Z] +++ /Users/ec2-user/jenkins/workspace/swift-PR-macos-smoke-test/branch-main/build/buildbot_incremental/swift-macosx-x86_64/test-macosx-x86_64/abi/macOS/x86_64/Output/stdlib-asserts.swift.tmp/symbols	2025-05-21 17:55:46
[2025-05-21T17:55:46.866Z] @@ -3385,6 +3385,7 @@
[2025-05-21T17:55:46.866Z]  _$sSo19_SwiftStdlibVersionas23CustomStringConvertiblesWP
[2025-05-21T17:55:46.866Z]  _$sSo19_SwiftStdlibVersionasE11descriptionSSvg
[2025-05-21T17:55:46.866Z]  _$sSo19_SwiftStdlibVersionasE11descriptionSSvpMV
[2025-05-21T17:55:46.866Z] +_$sSo19_SwiftStdlibVersionasE6v6_3_0ABvpZMV
[2025-05-21T17:55:46.866Z]  _$sSo19_SwiftStdlibVersionasE7currentABvgZ
[2025-05-21T17:55:46.866Z]  _$sSp10deallocate8capacityySi_tF
[2025-05-21T17:55:46.866Z]  _$sSp10deallocateyyF
[2025-05-21T17:55:46.866Z] 
[2025-05-21T17:55:46.866Z] --
[2025-05-21T17:55:46.866Z] Command Output (stderr):

[lorentey]

@swift-ci smoke test