a4df912018
This is a refactor of collision_driver and some of its surrounding code in order to prepare for condim in MJX. In this change we reify types that are needed for condim: dim, efc_address, efc_type. We make explicit the way contacts are organized and grouped to guarantee that dim and efc_type are statically defined. This change simplifies the way meshes are organized on device and slightly speeds up mesh collisions for cases where a single mesh is instanced across many geoms. PiperOrigin-RevId: 626119500 Change-Id: Ic0c8599bcda2326f2e19cd3246a673e56097886b