[llvm] AMDGPU/GlobalISel: Add test showing s_andn2_b32/b64 is not formed from booleans (PR #115537)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> I can see that s_andn2 is not formed in these tests, but I can't see how it would be any better if it was formed. What's the point of this?

The compares got negated, but that's not always possible. A better test would probably use an i1 in SGPR argument 

https://github.com/llvm/llvm-project/pull/115537