[llvm] [InstCombine] Add CTLZ -> CTTZ simplification (PR #164733)

[Mihail Mihov via llvm-commits]

MihailMihov wrote:

@nikic thanks for the review. I don't have commit access, so if I understood things correctly, I should ask you to squash and merge this on my behalf.

https://github.com/llvm/llvm-project/pull/164733