mpiCheckPhaseHook: update to use openmpi-5 compatible parameters

  case $mpiType in

    openmpi)

      # make sure the test starts even if we have less than the requested amount of cores

      # Note, that openmpi-5 switched to using PRRTE.

      # Thus we need to set PRTE_MCA_* instead of OMPI_MCA_*.

      # We keep the openmpi-4 parameters for backward compatability.

      # Make sure the test starts even if we have less than the requested amount of cores

      export OMPI_MCA_rmaps_base_oversubscribe=1

      export PRTE_MCA_rmaps_default_mapping_policy=node:oversubscribe

      # Disable CPU pinning

      export OMPI_MCA_hwloc_base_binding_policy=none

      export PRTE_MCA_hwloc_default_binding_policy=none

      ;;

    MPICH)

      # Fix to make mpich run in a sandbox