The type `Hasher._Core` is `@frozen` but its stored properties are `private`, which currently makes them show up in api-digester ABI reports, leading to failures like this one:
```
+Var Hasher._Core._buffer has mangled name changing from 'Swift.Hasher._Core.(_buffer in _A19879A32F7D08A6DD54BABBA00BBA0C) : Swift.Hasher._TailBuffer' to 'Swift.Hasher._Core.(_buffer in _16630011A164FCBB1F12E5E0A3A7C863) : Swift.Hasher._TailBuffer'
```
These names aren't ABI impacting, so this checker probably should ignore their name changes. (The property names do appear in the .swiftinterface files, but IIUC the only their type and ordering matters.)
These ever-changing unstable ids make it impossible to add an entry to the expectation list that would allow these tests to pass. Work around this issue by postprocessing the reports to replace the unstable parts with the constant string `#UNSTABLE ID#`.
rdar://82552099
These were defined for both FixedWidthInteger and FixedWidthInteger & SignedInteger for source compatibility with Swift 3; the latter set probably should have been removed when we stabilized the ABI, but were not. We can't easily remove them entirely (because we need them for ABI stability now), but we can mark them unavailable so that the typechecker doesn't have to consider them..
* Casting from AnyHashable to AnyHashable should never create another wrapper
This adds a conformance for _HasCustomAnyHashableRepresentation to
AnyHashable that simply returns self. This ensures that anytime
you try to create a new AnyHashable wrapper for an existing
AnyHashable, you just get back the original.
Resolves rdar://75180619
* Move the `Struct AnyHashable` change to `without-asserts` list
As suggested by @lorentey
