[llvm] [SelectionDAG] Handle more opcodes in canCreateUndefOrPoison (PR #84921)

[David Spickett via llvm-commits]

DavidSpickett wrote:

As this updated some tests, I've had to revert it while reverting https://github.com/llvm/llvm-project/pull/85932. I've put the details on that PR.

If this is actually unrelated to that feel free to reland, I just wasn't going to to be able to resolve the test file conflict myself so I went with the safest option.

https://github.com/llvm/llvm-project/pull/84921