[llvm] [LAA] Rewrite findForkedPointer (NFC) (PR #140298)

[Florian Hahn via llvm-commits]

https://github.com/fhahn commented:

Taking a step back, it might be good to revisit the goal of the PR. Overall it looks to me like the new code isn't much simpler and adds more indirection.

How about just combining `findForkedPointer` and `findForkedSCEVs`? 

https://github.com/llvm/llvm-project/pull/140298