[InstCombine] try to forward-propagate some FMF to select

[InstCombine] try to forward-propagate some FMF to select

This is intended to mitigate potential regressions that
would result from restricting this fold for NANs as
discussed in issue #59279.

Ideally, we could do this more generally because we have
known problems seeing/generating FMF on a select, but there
are likely many corner cases that need to verified.

For example, I thought this propagation would be valid
without looking at the condition value and for 'nsz' too,
but according to Alive2, it is not:
https://alive2.llvm.org/ce/z/AnG6As