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

[Shilei Tian via llvm-commits]

shiltian wrote:

> A light breeze can cause blender to fail. Any random code perturbation will break it until the WWM spilling patches are committed

Very likely the case. I checked the IR of my previously reverted PR. The only difference between the working version and mine is an extra address space cast, which is legit. Then it fails the blender test.

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