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.
