Protocol name mangling didn’t always go through a path that allowed the use
of standard substitutions. Enable standard substitutions for protocol name
manglings where they make sense.
Removes ~277k from the standard library binary size.
* [runtime] Clean up symbols in error machinery.
* [runtime] Clean up symbols in Foundation overlay.
* [runtime] Clean up symbols in collections and hashing.
* [runtime] Remove symbol controls from the Linux definition of swift_allocError.
* [tests] Add more stub functions for tests that link directly to the runtime.
If the Swift error wrapped in a _SwiftNativeNSError box conforms to
Hashable, the box now uses the Swift's conformance to Hashable.
Part of rdar://problem/27574348.
