[llvm] [AMDGPU] Allow shinking instruction with dead sdst (PR #68028)

[Stanislav Mekhanoshin via llvm-commits]

rampitec wrote:

> > > Oh, have you noticed that apart from `ds-combine-large-stride.ll`, every codegen diff is in a globalisel test, or a test with a globalisel RUN line? That seems odd.
> > 
> > 
> > That does not seem odd to me. These are the tests using auto-gen tests. I do not like these tests exactly for this reason.
> 
> You do not like these tests because they show the effect of your patch?
> 
> Then can you please include a `.ll` test that shows the effect of your patch on selectiondag codegen?

I do not like these mostly because no one does care. And because these do not highlight actual changes, it tends to include 140+ ours passes impact. Here we are, I am just following our pattern. If you want a specific test please tell me, as this patch has nothing to do with the isel.

https://github.com/llvm/llvm-project/pull/68028