dispose of the resources at the end of the paint deletion.
This will help retain the resources of the retained paints
and reuse them after reconstructing the next scene.
Get rid of the polymorphism function table,
use the switch directly instead.
We profiled, both binary & performance is better than before.
Tested on a local machine (single thread):
- Lottie: 2ms improved
- Binary: -0.5kb
This correction ensures a consistent use of 'ref' and 'unref' for paints to release memory properly.
The memory leak occurred when a picture was not pushed to a valid canvas.
This issue was reported by the unit-test memory sanitizer.
