AMDGPU/GlobalISel: Lower 64-bit uaddo/usubo

Summary: Add more test cases for signed and unsigned add/sub with overflow.

Reviewers: arsenm, rampitec, kerbowa

Subscribers: kzhuravl, jvesely, wdng, nhaehnle, yaxunl, rovka, dstuttard, tpr, t-tye, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D75051