[llvm] [NVPTX] don't erase CopyToRegs when folding movs into loads (PR #149393)

[Nikolay Panchenko via llvm-commits]

npanchen wrote:

@Prince781 can this be merged ? That should fix lots of stability issues we got after https://github.com/llvm/llvm-project/pull/126337

https://github.com/llvm/llvm-project/pull/149393