[llvm] [AMDGPU][SIPreEmitPeephole] mustRetainExeczBranch: use BranchProbability and TargetSchedmodel (PR #109818)

[Juan Manuel Martinez Caamaño via llvm-commits]

jmmartinez wrote:

Due to a bad git manipulation I've pushed amd/if-cvt-v2-machine-trace in here; I've removed that last commit.

https://github.com/llvm/llvm-project/pull/109818