[llvm] [MachineLateInstrsCleanup] Handle multiple kills for a preceding definition. (PR #119132)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> If there actually is a serious user, maybe that pass could instead recompute them and also be able to trust them fully.

No, there should be no users. All users should be changed to not rely on kill flags 

https://github.com/llvm/llvm-project/pull/119132