Remove kinematic bodies from graph coloring #917
Description
Similar to static bodies, the constraint solver does not need to write to kinematic body state. This means that we could ignore them from graph coloring, since we can have read-only access to the body state from multiple threads without race conditions. This would improve parallelism and multi-threaded scaling for large kinematic bodies touching many dynamic bodies.
See erincatto/box2d#970 for an equivalent change and "kinematic washer" sample in Box2D.