add tests for IncidentPhoton.from_hdf5
add tests for IncidentPhoton.from_hdf5

liangjg/openmc,liangjg/openmc,walshjon/openmc,shikhar413/openmc,smharper/openmc,walshjon/openmc,smharper/openmc,paulromano/openmc,wbinventor/openmc,amandalund/openmc,liangjg/openmc,walshjon/openmc,smharper/openmc,paulromano/openmc,mit-crpg/openmc,walshjon/openmc,mit-crpg/openmc,paulromano/openmc,wbinventor/openmc,liangjg/openmc,amandalund/openmc,shikhar413/openmc,mit-crpg/openmc,shikhar413/openmc,smharper/openmc,paulromano/openmc,wbinventor/openmc,shikhar413/openmc,wbinventor/openmc,amandalund/openmc,amandalund/openmc,mit-crpg/openmc