[mlir][spirv] Support `spirv.coopmatrix` type (de-)serialization (#65831)

Extend SPIR-V target serialization and deserialization to handle coop
matrix types. Add a roundtrip test. In addition to `FileCheck` checks,
the resulting spirv binary also passes `spir-val` (external tool).

Also fix a type attribute bug surfaced by the `CooperativeMatrixLength`
op.

Multiple matrix operand attributes will be handled in a future patch to
reduce the scope.