[llvm] Reland "[InstCombine] Fold (sub nuw X, (Y << nuw Z)) >>u exact Z --> (X >>u exact Z) sub nuw Y" (PR #93571)

[Nikita Popov via llvm-commits]

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

LGTM.

I'll merge this on Monday if nobody beats me to it.

https://github.com/llvm/llvm-project/pull/93571