Originally was noticed when using a linked background scene and a scene
camera from another (local) scene.
The root issue was that relation from view layer to object's base flags
evaluation was using wrong view layer. This is because the relation was
created between object and currently built view layer, and it only was
happening once (since the object-level relations are only built once).
Depending on order in which build_object was called it was possible
that relation from a wrong view layer was used.
Now the code is better split to indicate which parts of object relations
are built when object comes from a base in the view layer, and which ones
are built on indirect linking of object to the dependency graph.
This patch makes relations correct in the cases when the same object is
used as a base in both active and set scenes. But, the operation which
handles object-level flags might not behave correctly as there is no
known design of what is the proper thing to do in this case. Making a
clear design and implementation of case when object is shared between
active and set scene is outside of the scope of this patch.