SR-5591: Update broken DateFormatter tests
SR-5591: Update broken DateFormatter tests

- The tests were broken for timestyle .full and failed on macOS.
  Fix the tests so that they work correctly on macOS.

- DateFormatter is still broken on Linux so disable the tests for
  now until the Linux implementation can be fixed.

apple/swift-corelibs-foundation,e78l/swift-corelibs-foundation,alblue/swift-corelibs-foundation,amraboelela/swift-corelibs-foundation,ikesyo/swift-corelibs-foundation,mattrajca/swift-corelibs-foundation,johnno1962c/swift-corelibs-foundation,mattrajca/swift-corelibs-foundation,alblue/swift-corelibs-foundation,johnno1962e/swift-corelibs-foundation,e78l/swift-corelibs-foundation,e78l/swift-corelibs-foundation,bolshedvorsky/swift-corelibs-foundation,bolshedvorsky/swift-corelibs-foundation,johnno1962b/swift-corelibs-foundation,amraboelela/swift-corelibs-foundation,apple/swift-corelibs-foundation,mattrajca/swift-corelibs-foundation,JGiola/swift-corelibs-foundation,bolshedvorsky/swift-corelibs-foundation,ikesyo/swift-corelibs-foundation,e78l/swift-corelibs-foundation,amraboelela/swift-corelibs-foundation,JGiola/swift-corelibs-foundation,parkera/swift-corelibs-foundation,e78l/swift-corelibs-foundation,amraboelela/swift-corelibs-foundation,johnno1962e/swift-corelibs-foundation,amosavian/swift-corelibs-foundation,parkera/swift-corelibs-foundation,JGiola/swift-corelibs-foundation,mattrajca/swift-corelibs-foundation,johnno1962e/swift-corelibs-foundation,apple/swift-corelibs-foundation,JGiola/swift-corelibs-foundation,johnno1962c/swift-corelibs-foundation,johnno1962e/swift-corelibs-foundation,johnno1962c/swift-corelibs-foundation,parkera/swift-corelibs-foundation,johnno1962e/swift-corelibs-foundation,johnno1962c/swift-corelibs-foundation,mattrajca/swift-corelibs-foundation,johnno1962b/swift-corelibs-foundation,amraboelela/swift-corelibs-foundation,bolshedvorsky/swift-corelibs-foundation,johnno1962b/swift-corelibs-foundation,amosavian/swift-corelibs-foundation,johnno1962c/swift-corelibs-foundation,apple/swift-corelibs-foundation,johnno1962b/swift-corelibs-foundation,ikesyo/swift-corelibs-foundation,alblue/swift-corelibs-foundation,JGiola/swift-corelibs-foundation,ikesyo/swift-corelibs-foundation,parkera/swift-corelibs-foundation,alblue/swift-corelibs-foundation,alblue/swift-corelibs-foundation,amosavian/swift-corelibs-foundation,ikesyo/swift-corelibs-foundation,amosavian/swift-corelibs-foundation,apple/swift-corelibs-foundation,amosavian/swift-corelibs-foundation,parkera/swift-corelibs-foundation,johnno1962b/swift-corelibs-foundation,bolshedvorsky/swift-corelibs-foundation