[llvm] [MachineScheduler][AMDGPU] Allow scheduling of single-MI regions (PR #128739)

[Shilei Tian via llvm-commits]

https://github.com/shiltian commented:

Am I looking at the right diff here? The only code change shown here is the removal of `I == std::prev(RegionEnd)`.

https://github.com/llvm/llvm-project/pull/128739