Resources are shared, when running multiple contexts on the same thread.
Cycles uses the same context on multiple threads and expected same resources.
This change will introduce a single render graph per context and an updated
resource management. Render graphs are not shared anymore; Resource pools
are still shared, but garbage collection depends on the thread and if
background rendering is used.
Pull Request: https://projects.blender.org/blender/blender/pulls/128983
d35cd15e12