Blender Git Loki

Depsgraph: Traversing should be consistent for nodes and relationship

We need to traverse the same exact objects for both nodes and relationship
builder. We were using FOREACH_SCENE_OBJECT for relationships, which
would lead to plenty of warnings in multiple situations.

In the future we will need to change this to build the depsgraph
relations and nodes to one single render_layer.

Fix T51780: If an object is in two collections and I do a full copy of
scene things go bad