[llvm] [llvm][NVPTX] Fix quadratic runtime in ProxyRegErasure (PR #105730)

[Jeff Niu via llvm-commits]

Mogball wrote:

Got it. I found the bug. The issue is something like

```
%1 = mov %0
%2 = mov %1

use %0
use %0
use %1
```

I have a fix and I'm just trying to figure out how to write an MIR test!

https://github.com/llvm/llvm-project/pull/105730