Add ObjCMethodDecl.IsPropertyAccessor. #527

Job	Run time
macos-arm64 (arm64, debug, macos)	3m 14s
windows-arm64 (arm64, debug, windows)	5m 41s
windows-x64 (x64, release, windows)	6m 26s
macos-arm64 (arm64, release, macos)	5m 44s
linux-arm64 (arm64, release, ubuntu)	3m 31s
linux-x64 (x64, debug, ubuntu)	3m 35s
windows-arm64 (arm64, release, windows)	7m 32s
windows-x64 (x64, debug, windows)	6m 12s
linux-x64 (x64, release, ubuntu)	3m 39s
linux-arm64 (arm64, debug, ubuntu)	3m 31s
sign-nuget	0s
publish-nightlies-azure	0s
publish-nightlies-github	0s
	49m 5s

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