[MLIR][OpenMP] Host lowering of distribute-parallel-do/for (#127819)
This patch adds support for translating composite `omp.parallel` +
`omp.distribute` + `omp.wsloop` loops to LLVM IR on the host. This is
done by passing an updated `WorksharingLoopType` to the call to
`applyWorkshareLoop` associated to the lowering of the `omp.wsloop`
operation, so that `__kmpc_dist_for_static_init` is called at runtime in
place of `__kmpc_for_static_init`.
Existing translation rules take care of creating a parallel region to
hold the workshared and workdistributed loop.