x86 CodeGen: MO_S_MulMayOflo handle W8 and W16
The test-primops
testsuite unveiled that these width can actually appear: https://gitlab.haskell.org/ghc/test-primops/-/jobs/1573411#L4898
This MR implements them.
It's debatable if the additional test is needed as this is covered by test-primops
. I've mostly added it to show to the reviewer that the generated code works.