[llvm] [RISCV][GISel][NFC] Add MIR legalizer tests for G_UADDE (rv32 & rv64) (PR #152827)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm commented:

What's the reason to add these? I would expect this to already be covered, and in general end to end IR tests are easier to maintain 

https://github.com/llvm/llvm-project/pull/152827