[llvm] SelectionDAG: Use qNaN constant if FCANONICALIZE not LegalOrCustom (PR #104564)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> @arsenm is it acceptable if we don't require keeping payload?

Yes. Payload preservation is a nice to have, not a requirement 

https://github.com/llvm/llvm-project/pull/104564