* Improve materials under white furnace test
Two major changes:
- Mobile target now implements a cheaper variant of the off specular
peak bias (which moves the reflected vector towards the normal).
This greatly helps with rough surfaces that may otherwise point
toward a bright part of the IBL.
- The indirect diffuse love is now properly attenuated to avoid adding
the energy reflected by the specular layer. This allows dielectrics
to be correctly energy conserving under a white furnace.
- Tweak the (hacky) clear coat layer attenuation to behave properly
under a white furnace.
* Use the same reflected vector modification everywhere