[llvm] [NVPTX] Constant-folding for f2i, d2ui, f2ll etc. (PR #118965)

[Alex MacLean via llvm-commits]

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

LGTM with one minor nit you can ignore if you want

https://github.com/llvm/llvm-project/pull/118965