[llvm] [AMDGPU] Re-enable closed-world assumption as an opt-out feature (PR #115371)

[Joseph Huber via llvm-commits]

jhuber6 wrote:

> I don't know what this is supposed to mean. Who checks llvm.global_ctors? The driver? The pass?
> 
> The former cannot, and the latter will analyzes uses and act on the flag as defined, I don't see how that interacts with llvm.global_ctors.

The ctors global needs to be counted as a user of the function if it contains it.

https://github.com/llvm/llvm-project/pull/115371