[llvm] ObjCARCContract: Use stripPointerCastsAndAliases (PR #134275)

[Nikita Popov via llvm-commits]

nikic wrote:

I'm not convinced that the replacement with stripPointerCastsAndAliases() makes sense. Yes, this does something similar, but the important difference is that the current code performs the replacement at *each* instruction in the chain. Now you are only doing it at the first and last value in the chain, which is not the same.

https://github.com/llvm/llvm-project/pull/134275