[llvm] [InstCombine] [X86] pblendvb intrinsics must be replaced by select when possible (PR #137322)

[Simon Pilgrim via llvm-commits]

https://github.com/RKSimon commented:

You don't need the new blend.ll file - we already have test coverage in PhaseOrdering/X86

https://github.com/llvm/llvm-project/pull/137322