[llvm] AMDGPU: Add baseline tests for gep flag handling (PR #110814)

[Nico Weber via llvm-commits]

nico wrote:

Looks like these are failing: http://45.33.8.238/linux/149769/step_11.txt

Please take a look and revert for now if it takes a while to fix.

https://github.com/llvm/llvm-project/pull/110814