Decorates inline helpers in blackoil*modules.hh, blackoilprimaryvariables.hh,
directionalmobility.hh, tpfalinearizer.hh, NewTranFluxModule.hpp,
TemperatureModel.hpp and BlackOilEnergyIntensiveQuantitiesGlobalIndex.hpp
with OPM_HOST_DEVICE, replaces a few raw `throw`s with OPM_THROW, and
switches static `FluidSystem::` accesses to instance-based
`fluidState.fluidSystem()` / `getFluidSystem()` so the same code works
when the fluid system lives on the device. Test
test_gpu_linear_two_phase_material.cu picks up the matching template
adjustments.