[llvm] [AMDGPU] Add mark last scratch load pass (PR #75512)

[Vladimir Vereschaka via llvm-commits]

vvereschaka wrote:

@mbrkusanin ,

the `LLVM::vgpr-mark-last-scratch-load.mir` test gets failed on the expensive check builders here

* https://lab.llvm.org/buildbot/#/builders/104/builds/15165
* https://lab.llvm.org/buildbot/#/builders/16/builds/59785
* https://lab.llvm.org/buildbot/#/builders/42/builds/12998


https://github.com/llvm/llvm-project/pull/75512