[llvm] [SimplifyCFG] Relax `cttz` cost check in `simplifySwitchOfPowersOfTwo` (PR #145159)

[Nikita Popov via llvm-commits]

https://github.com/nikic commented:

I think relaxing this to 2 is fine. Can you add an x86 test?

https://github.com/llvm/llvm-project/pull/145159