[llvm] [InstCombine] Support well-defined recurrences in isGuaranteedNotToBeUndefOrPoison (PR #150420)

[Cullen Rhodes via llvm-commits]

c-rhodes wrote:

Abandoning this in favour of https://github.com/llvm/llvm-project/pull/154336. Might be able to pull propagation of assumption cache to support assume out of this patch as that still seems useful, but at least one of the tests I added for that will need reworking, so I'll wait for that PR to land first.

https://github.com/llvm/llvm-project/pull/150420