[llvm] [AMDGPU] Don't fix the scavenge slot at offset 0 (PR #79136)

[Diana Picus via llvm-commits]

rovka wrote:

Ok, thanks. @mariusz-sikora-at-amd is investigating an issue that might be related to the scavenging slot, so hopefully that will help get some better test coverage.

https://github.com/llvm/llvm-project/pull/79136