Unify unlifted pointer equality primitives
We have a bunch of different primops to test pointer equality between various unlifted pointer types (
MutVar#, etc.). Now that we have the necessary type machinery, I believe we should be able to get away with just one:
unliftedPtrEquality# :: forall (a :: TYPE 'UnliftedRep). a -> a -> Int#
All the rest can then be defined as regular functions in
GHC.Exts or some such.