[llvm] [llvm][NVPTX] Fix RAUW bug in NVPTXProxyRegErasure (PR #105871)

[Jeff Niu via llvm-commits]

Mogball wrote:

I'm getting more reports of breakages coming from downstream projects, so I'm going to go ahead and land this to fix-forward. If you have any more comments on the PR, I am happy to address them in follow ups! Thanks for the review and testing tips

https://github.com/llvm/llvm-project/pull/105871