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

[Thorsten Schütt via llvm-commits]

tschuett wrote:

https://github.com/llvm/llvm-project/blob/32913724acf9e02beed46999fee1424086b8c884/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp#L4323

The lowering of G_UADDE blindly adds the CarryIn to the sum of

https://github.com/llvm/llvm-project/blob/32913724acf9e02beed46999fee1424086b8c884/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp#L4318 

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