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

[Björn Pettersson via llvm-commits]

bjope wrote:

I've rebased this patch (since for example the orignally planned changes releated to EXTRACT_VECTOR_ELT has landed via other patches).
- The new version is including some special limitations for SRA/SRL in DAGCombiner::visitFreeze, due to the problems seen in earlier attempts to handle those operations. The test cases I had planned for SRA/SRL was however pre-committed already in commit 4d0f79e346ceb0ddb25a9.
- I've dropped everything related to SELECT for now (but SELECT_CC is still handled).

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