Blender Git Loki

Smoke: Don't allocate arrays needed for hi-res simulation if smoke is baked to file

There used to be quite huge 3D arrays stored in memory which are only needed for
simulation steps and not used at all if the smoke is baked to file. That memory
is unmanaged by blender and not visible in the info space header and in practice
they could easily be gigabytes for hires smoke.

This commit only addressed hires smoke since it's the more important at this
point, and non-hires smoke wouldn't have such noticeable benefit.

In the case of tornado file it gives around 20% memory saving (which is about
26GB vs. 33GB on later frames of 01.03.02.A3 shot.