LU-13086 tests: restore compatibility with mpich

LU-13086 tests: restore compatibility with mpich

The addition of the --oversubscribe MPI option to mpi_run() is
OpenMPI specific.  Patch moves --oversubscribe to MPIRUN_OPTIONS
in local.sh to restore the compatibility with MPICH.

Test-Parameters: trivial clientdistro=el8.3 serverdistro=el7.7 testlist=parallel-scale,large-scale,performance-sanity
Test-Parameters: clientdistro=el8.4 serverdistro=el7.7 testlist=parallel-scale,large-scale,performance-sanity
Fixes: 3c7aca7472 ("LU-12395 build: build mpitests for el8")
Cray-bug-id: LUS-8006
Signed-off-by: Elena Gryaznova <elena.gryaznova@hpe.com>
Change-Id: I0a6fab072212781d12877d2503ae8600cfdc8c7a
Reviewed-on: https://review.whamcloud.com/38689
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Andriy Skulysh <andriy.skulysh@hpe.com>
Reviewed-by: James Nunez <jnunez@whamcloud.com>