Previously, objects and geometries were mapped between frames using different hash tables in a way that is incompatible with geometry instances. That is because the geometry mapping happened without looking at the `persistent_id` of instances, which is not possible anymore. Now, there is just one mapping that identifies the same object at multiple points in time. There are also two new caches for duplicated vbos and textures used for motion blur. This data has to be duplicated, otherwise it would be freed when another time step is evaluated. This caching existed before, but is now a bit more explicit and works for geometry instances as well. Differential Revision: https://developer.blender.org/D13497