[llvm] Adding abdu/abds to canCreateUndefOrPoison (PR #149017)

[Annu Singh via llvm-commits]

AnnuCode wrote:

@RKSimon thanks! Now I understand why to include final truncation in the Alive2 tests, as it completes the generic pattern of abdu/s. Here are the tests: 
- [Alive2 abdu](https://alive2.llvm.org/ce/z/aafeJs)
- [Alive2 abds](https://alive2.llvm.org/ce/z/XrSmP4)

https://github.com/llvm/llvm-project/pull/149017