[llvm] [AMDGPU] Remove the AnnotateKernelFeatures pass (PR #130198)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> > Should also add a test for what happens on undefined behavior, and flat_scratch does end up really getting used. We shouldn't have any verifier errors or anything
> 
> Please elaborate on "undefined behavior".

The contract of amdgpu-no-flat-scratch-init is violated and flat_scr requires initialization. i.e. addrspacecast of a private address to flat 

https://github.com/llvm/llvm-project/pull/130198