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

[via llvm-commits]

agozillon wrote:

Just a small ping to check if you're happy with the fix as is @kiranchandramohan or if you'd prefer me to dig into the block merge/splice method to see if it's feasible? 

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