[llvm] [AMDGPU][Scheduler] Refactor ArchVGPR rematerialization during scheduling (PR #125885)

[Pierre van Houtryve via llvm-commits]

Pierre-vh wrote:

It's just a few instructions that moved, I regenerated the test and committed it directly: 382a085a95b0abeac77b150b7b644b372bd08e78

https://github.com/llvm/llvm-project/pull/125885