[llvm] [AMDGPU] Add verifier for flat_scr_base_hi read hazard (PR #170550)

[Jay Foad via llvm-commits]

https://github.com/jayfoad commented:

No real objection but... shouldn't verifyInstruction call isOperandLegal on all operands so that we don't have to duplicate checks like this?

https://github.com/llvm/llvm-project/pull/170550