Blender Git Loki

WIP: Cycles X: Schedule work based on occupancy

Sacrifice refresh interval and increase GPU occupancy, lowering the
final render time.

Lowers `Blender 2.80 - Spring` demo file form predicted 30min
measured 3 min to render 1/10th of samples) to about 7.5min.

It is still considerably higher than the master branch, which finishes
the file in just below 3 min, but it is already a better results.

The timing is from RTX 5000.

The viewport and CPU rendering should stay unaffected by this change.

Differential Revision: https://developer.blender.org/D12570