[llvm] [AMDGPU] Modify Dyn Alloca test to account for Machine-Verifier bug (PR #120393)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> > This is just a bug that should be fixed, not a behavior to consider
> 
> I need to modify the run line of this test file before pre-committing other tests for dynamic allocas. #120063 Another option is to remove the `-verify-machineinstrs` flag from the run line until this bug is resolved.

You would need an explicit -verify-machineinstrs=0 to avoid breaking EXPENSIVE_CHECKS builds 

https://github.com/llvm/llvm-project/pull/120393