swift234

[stdlib] removed ambiguous String comparison overloads

Fixes rdar://problem/19169066

Now that some implicit bridging conversions were removed, we can remove some of
the complex String comparison overloads. We could not remove all of them yet, as
String to NSString implicit bridging still exists. To work around this,
unavailable annotations were used. This ensures the user always gets the String
comparison function they intended.

Swift SVN r24536