Blender Git Loki

DRW: Opti: Fix hotspot in DRW_mesh_batch_cache_get_surface_shaded

The hotspot was generated by mesh_cd_layers_type_overlap who was testing
way more data than it should have.

Here we reduce the whole CD layer mask to a 32bit bitflag that is easily
or'ed and tested.

Bonus point: We use atomic operation to merge the mask in order to allow
future multi-threading. (this was a TODO)

In the scene attached to T58188 this removes 5% of CPU time.