Re-apply "[AMDGPU] Fix test failures when expensive checks are enabled (#130644)"

As suggested on
5ec884e#commitcomment-153707488
this seems to fix the following tests when building with -DLLVM_ENABLE_EXPENSIVE_CHECKS=ON:

  LLVM :: CodeGen/AMDGPU/materialize-frame-index-sgpr.gfx10.ll
  LLVM :: CodeGen/AMDGPU/materialize-frame-index-sgpr.ll
  LLVM :: CodeGen/AMDGPU/schedule-amdgpu-tracker-physreg-crash.ll

> This PR fixes test failures introduced in #127353 when expensive checks
> are enabled.
>
> For `llvm/test/CodeGen/AMDGPU/materialize-frame-index-sgpr.ll` and
> `llvm/test/CodeGen/AMDGPU/materialize-frame-index-sgpr.gfx10.ll`, `s59`
> is no longer in live-ins because it is caller saved. Switch to `s55` in
> this PR.

Author: shiltian