Also handle the case where advection is integrated by parts in the multiphase internal energy equation.
Also handle the case where advection is integrated by parts in the multiphase internal energy equation.

jjo31/ATHAM-Fluidity,jrper/fluidity,iakovos-panourgias/fluidity,jrper/fluidity,rjferrier/fluidity,iakovos-panourgias/fluidity,jrper/fluidity,iakovos-panourgias/fluidity,jrper/fluidity,rjferrier/fluidity,iakovos-panourgias/fluidity,jrper/fluidity,jjo31/ATHAM-Fluidity,jjo31/ATHAM-Fluidity,jjo31/ATHAM-Fluidity,jjo31/ATHAM-Fluidity,rjferrier/fluidity,iakovos-panourgias/fluidity,rjferrier/fluidity,rjferrier/fluidity