[llvm] [X86] Prefer andl to andb to save one byte encoding when using with bzhi or bextr (PR #86921)

[Danila Malyutin via llvm-commits]

danilaml wrote:

I'm still not sure this is the best place to implement this, if we really want it (I defer to others on this). The optimization seems general enough to me for it to live in this specific place and I'm not sure we can guarantee that other optimizations don't produce similar code and needs similar fix ups. Aren't there any sort of peephole x86 machine passes that swap instructions with equivalent acting on smaller sizes to save on size?

https://github.com/llvm/llvm-project/pull/86921