[llvm] [mlir] [OpenMP][MLIR][OMPIRBuilder] Add a small optional constant alloca raise function pass to finalize, utilised in convertTarget (PR #78818)

[Kiran Chandramohan via llvm-commits]

https://github.com/kiranchandramohan approved this pull request.

I think constant allocas are fine to be hoisted. But as mentioned elsewhere there could be other cases where allocas might cause problems and might require a generic solution.

If there are no concerns expressed in a day or two you can consider submitting this patch and generalize this later on.

https://github.com/llvm/llvm-project/pull/78818