Update Darwin availability annotations. #93743

Job	Run time
Build framework (macos-release, -sdk macosx -configuration Release)	15m 17s
Build framework (macos-release, -sdk macosx -configuration Release)	15m 17s
Build framework (ios-release, -sdk iphoneos -configuration Release)	7m 20s
Build framework (ios-release, -sdk iphoneos -configuration Release)	7m 20s
Build framework (tvos-debug, -sdk appletvos -configuration Debug)	8m 52s
Build framework (tvos-debug, -sdk appletvos -configuration Debug)	8m 52s
Build framework (watchos-debug, -sdk watchos -configuration Debug)	9m 4s
Build framework (watchos-debug, -sdk watchos -configuration Debug)	9m 4s
Run framework tests (asan, -enableAddressSanitizer YES -enableUndefinedBehaviorSanitizer YES)	22m 45s
Run framework tests (asan, -enableAddressSanitizer YES -enableUndefinedBehaviorSanitizer YES)	22m 46s
Run framework tests (tsan, -enableThreadSanitizer YES)	22m 34s
Run framework tests (tsan, -enableThreadSanitizer YES)	20m 52s
Run framework tests (leaks, ENABLE_LEAK_DETECTION=1)	23m 33s
Run framework tests (leaks, ENABLE_LEAK_DETECTION=1)	21m 58s
	3h 35m 34s

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