[clang] [llvm] [DropUnnecessaryAssumes] Add pass for dropping assumes (PR #159403)

[Ramkumar Ramachandra via llvm-commits]

https://github.com/artagnon approved this pull request.

LGTM, thanks! I will investigate a follow-up related to my question.

https://github.com/llvm/llvm-project/pull/159403