[CoreFoundation] Revert some Android regressions that crept in
[CoreFoundation] Revert some Android regressions that crept in

Revert an Android-specific block that was already removed in #2168 and don't
check for baseURL in _CFTimeZoneInit(), since Android doesn't use it anyway.

apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation