Making the constraint a buildable type makes them incompatible with opaque pointers, at least while we still support typed pointers, since Ops making use of the constraint will then automatically create a typed pointer on parse.
This patch therefore fixes that issue by removing the `BuildableType` mixin. This has a bit of a cascading effect however, as all users of the constraint now need operands of that type to be added to the assembly format, hence a lot of adjustments to the syntax of a lot of (mostly intrinsic) ops.
Few things of note: The syntax as is, is only required while we're supporting both typed and opaque pointers. Once we drop support for typed pointers, we can make it a `BuildableType` again. As a drive by I also fixed the address space not being verified in the constraint. Finally, I added some roundtripping tests, most importantly for ops with `type($specific_operand)` occurences. These are printed incorrectly with typed pointers if not wrapped within a `qualified`.
Differential Revision: https://reviews.llvm.org/D144479