Restore ADDITIONAL_CPPFLAGS to unit test Makefile for consistency with other modules
Restore ADDITIONAL_CPPFLAGS to unit test Makefile for consistency with other modules

laagesen/moose,sapitts/moose,lindsayad/moose,idaholab/moose,laagesen/moose,SudiptaBiswas/moose,milljm/moose,andrsd/moose,sapitts/moose,SudiptaBiswas/moose,laagesen/moose,nuclear-wizard/moose,andrsd/moose,harterj/moose,milljm/moose,harterj/moose,milljm/moose,sapitts/moose,SudiptaBiswas/moose,jessecarterMOOSE/moose,bwspenc/moose,idaholab/moose,harterj/moose,laagesen/moose,idaholab/moose,dschwen/moose,nuclear-wizard/moose,lindsayad/moose,lindsayad/moose,bwspenc/moose,sapitts/moose,dschwen/moose,harterj/moose,bwspenc/moose,andrsd/moose,idaholab/moose,nuclear-wizard/moose,SudiptaBiswas/moose,milljm/moose,sapitts/moose,harterj/moose,laagesen/moose,bwspenc/moose,dschwen/moose,jessecarterMOOSE/moose,jessecarterMOOSE/moose,idaholab/moose,andrsd/moose,andrsd/moose,lindsayad/moose,nuclear-wizard/moose,SudiptaBiswas/moose,milljm/moose,dschwen/moose,jessecarterMOOSE/moose,bwspenc/moose,jessecarterMOOSE/moose,lindsayad/moose,dschwen/moose