[llvm] [InstCombine][AMDGPU] Disable PtrReplacer when select has mismatch AS (PR #98456)

[via llvm-commits]

jofrn wrote:

> Should this be closed then? Is it worth keeping these tests?

Yes, it should. The tests were relevant to ensuring this algorithm was correct (checking both, one, or none). Both and none are already handled without any change, and @shiltian's handles the single load case.

https://github.com/llvm/llvm-project/pull/98456