[llvm] [InstCombine] Fix FMF propagation in `foldSelectIntoOp` (PR #114356)

[via llvm-commits]

dyung wrote:

This change also seems to be causing a test failure in `Transforms/LoopVectorize/ARM/mve-selectandorcost.ll`:
https://lab.llvm.org/buildbot/#/builders/174/builds/7674

https://github.com/llvm/llvm-project/pull/114356