[llvm] [InstCombine] Pull unary shuffles through fneg/fabs (PR #144933)

[Philip Reames via llvm-commits]

preames wrote:

Once this goes in, we should remember to make the analogous change for the shuffle-like intrinsics - i.e. reverse and vp.reverse.  

https://github.com/llvm/llvm-project/pull/144933