Introduce a type system for the transform dialect. A transform IR type
captures the expectations of the transform IR on the payload IR
operations that are being transformed, such as being of a certain kind
or implementing an interface that enables the transformation. This
provides stricter checking and better readability of the transform IR
than using the catch-all "handle" type.
This change implements the basic support for a type system amendable to
dialect extensions and adds a drop-in replacement for the unrestricted
"handle" type. The actual switch of transform dialect ops to that type
will happen in a separate commit.
See https://discourse.llvm.org/t/rfc-type-system-for-the-transform-dialect/65702
Reviewed By: nicolasvasilache
Differential Revision: https://reviews.llvm.org/D135164
