[llvm] InstCombine: fix transformation of bitwiseAnd to fabs (PR #71257)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm requested changes to this pull request.

The rationale for this change is incorrect. By definition, fabs, fneg, and copysign only change the sign bit and cannot make any other value modifications. Any lowering of these operations which do flush denormals or quiet signaling nans are incorrect and should be fixed

https://github.com/llvm/llvm-project/pull/71257