[llvm] [AMDGPU] Move `AMDGPUAttributorPass` to full LTO post link stage (PR #102086)

[Shilei Tian via llvm-commits]

shiltian wrote:

This and my previously reverted PR, as well as a SimplifyCFG related PR, almost broke the blender test in the same way. This can't be coincidental IMHO. It must expose something wrong in the AMDGPU backend.

https://github.com/llvm/llvm-project/pull/102086