[llvm] [NVPTX] Default to NewPM (PR #218756)

[Aiden Grossman via llvm-commits]

https://github.com/boomanaiden154 commented:

I think we probably want to hold off on this for now for major targets.

We need to finish up opt-bisect support, probably resolve the LSR LCSSA issues, and ensure a couple more frontends are wired up (likely pending a proper abstraction).

https://github.com/llvm/llvm-project/pull/218756