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

[Akira Hatanaka via llvm-commits]

ahatanak wrote:

Correction: with the changes in this patch, the pass no longer rewrites the argument to the *first* call to use_pointer in the following IR:

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