starpu: use starpu_mpi_wait_for_all when available
starpu_mpi_barrier is not really supposed to properly synchronize with STF.
[En cours] Mise en place de quotas sur nos instances GitLab. Plus d'information sur : https://doc-si.inria.fr/pages/viewpage.action?pageId=146834656
[In progress] Quotas installation on our GitLab instances. More information: https://doc-si.inria.fr/pages/viewpage.action?pageId=146834656
starpu_mpi_barrier is not really supposed to properly synchronize with STF.