Unify unlifted pointer equality primitives

We have a bunch of different primops to test pointer equality between various unlifted pointer types (MutableArray#, 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.

Trac metadata

Trac field	Value
Version	8.4.3
Type	FeatureRequest
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information

Admin message

Unify unlifted pointer equality primitives