[llvm] [Sched] Add MacroFusion mutation if fusions are not empty (PR #72227)

[Wang Pengcheng via llvm-commits]

wangpc-pp wrote:

> Can you update to what's already been merged? It's hard to see what's left here

Updated. All the stacked PRs have been merged.
Sorry for bothering, I myself have almost forgot about this PR...

https://github.com/llvm/llvm-project/pull/72227