[llvm] [GlobalISel] Fix [SU]SUBO combine (PR #116998)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> https://llvm.org/docs/GlobalISel/GenericOpcode.html#g-uadde-g-sadde-g-usube-g-ssube

This could use elaboration about the target boolean contents

https://github.com/llvm/llvm-project/pull/116998