Extend NSNumber bridging to cover not only `Int`, `UInt`, `Double`, and `Bool`, but all of the standard types as well. Extend the `TypePreservingNSNumber` subclass to accommodate all of these types, so that we preserve type identity for `AnyHashable` and dynamic casting of Swift-bridged NSNumbers. If a pure Cocoa NSNumber is cast, just trust that the user knows what they're doing.
This XFAILs a couple of serialization tests that attempt to build the Foundation overlay, but which don't properly handle `gyb` files.
We were using a precondition which crashes the program when invalid input is
provided. We want to provide a way to gracefully check and handle invalid input
or shutdown the program if necessary.
SR-1930
[stdlib] Fix the `String.decodeCString` for UTF16 and UTF32
Resolves [SR-1578](https://bugs.swift.org/browse/SR-1578]
Essentially the problem was that `strlen` is not the right way of
obtaining a length of anything but null-terminated UTF-8 sequence of
characters. Other encodings require alternative mechanisms.
