[llvm] [ARM] Remove `UnsafeFPMath` uses in code generation part (PR #160801)

[David Green via llvm-commits]

https://github.com/davemgreen approved this pull request.

Thanks, LGTM

There is a comment in `/// OptimizeVFPBrcond - With nnan and without daz` that could be pulled over too, either way is OK.

https://github.com/llvm/llvm-project/pull/160801