FindMPI: Factor out compiler wrapper execution into helper
FindMPI: Workaround Intel MPI 5.0.1 exit code problem (#15182)

This MPI compiler may return zero even in some error cases.  Check the
output to catch such cases.

Suggested-by: Kelly Thompson <kgt@lanl.gov>
Merge topic 'FindMPI-Intel-5.0.1' into next

7626c8dc FindMPI: Workaround Intel MPI 5.0.1 exit code problem (#15182)
f5ede300 FindMPI: Factor out compiler wrapper execution into helper