[llvm] [DAGCombiner] Turn `(neg (max x, (neg x)))` into `(min x, (neg x))` (PR #120666)

[Min-Yih Hsu via llvm-commits]

mshockwave wrote:

> Can you also do the globalisel version?

Of course. Let me do that in a separate PR.

https://github.com/llvm/llvm-project/pull/120666