Allow mpif90 in run_tests.py
Allow mpif90 in run_tests.py

smharper/openmc,samuelshaner/openmc,liangjg/openmc,shikhar413/openmc,johnnyliu27/openmc,walshjon/openmc,amandalund/openmc,walshjon/openmc,wbinventor/openmc,paulromano/openmc,kellyrowland/openmc,liangjg/openmc,samuelshaner/openmc,shikhar413/openmc,johnnyliu27/openmc,liangjg/openmc,wbinventor/openmc,mjlong/openmc,samuelshaner/openmc,smharper/openmc,wbinventor/openmc,samuelshaner/openmc,walshjon/openmc,amandalund/openmc,bhermanmit/openmc,johnnyliu27/openmc,liangjg/openmc,amandalund/openmc,mit-crpg/openmc,smharper/openmc,mit-crpg/openmc,bhermanmit/openmc,walshjon/openmc,smharper/openmc,johnnyliu27/openmc,mit-crpg/openmc,paulromano/openmc,shikhar413/openmc,wbinventor/openmc,mjlong/openmc,paulromano/openmc,shikhar413/openmc,paulromano/openmc,amandalund/openmc,mit-crpg/openmc,kellyrowland/openmc