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

[via llvm-commits]

agozillon wrote:

Probably worth noting this issue doesn't exist for the current variations of target parallel from what I've found, likely because the CodeExtractor magics the user code into a seperate function with an appropriate entry block (my knowledge on the lowering of parallel is still a WIP, so please take it with a grain of salt and anyone more familiar please feel free to override my statement). 

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