cmm: Add surface syntax for MO_MulMayOflo
Such that we can test #21624 (closed) with bgamari/test-primops>.
See https://gitlab.haskell.org/bgamari/test-primops/-/issues/2.
Such that we can test #21624 (closed) with bgamari/test-primops>.
See https://gitlab.haskell.org/bgamari/test-primops/-/issues/2.