Unlifted primop types

[David Feuer]

Huh! It looks like what we currently do for some primops is just use a totally bogus kind. For example, mkWeak# will happily accept an Int# as its first argument. So we *could* follow that precedent and generalize reallyUnsafePtrEquality#, makeStableName#, etc., to accept anything, whether it makes sense or not. Or we can work out how to do what I was trying to do and then duplicate those primitives as appropriate (mkLiftedWeak#, mkUnliftedWeak#, makeLiftedStableName#, makeUnliftedStableName#, etc.).