[llvm] [mlir] [mlir][gpu] Change GPU modules to globals (PR #135478)

[Christian Sigg via llvm-commits]

chsigg wrote:

I'm sorry this change is causing trouble for you. I'm not sure now, can you work with the current state or do you prefer to move the module global+ctor/dtor creation back to `createKernelLaunch`?

https://github.com/llvm/llvm-project/pull/135478