Ensemble8 Canvas Fireworks jitters while animating

To reproduce this:

1. Run Ensemble8

2. Select the "Graphics 2d" --> "Canvas Fireworks" sample

The position of the Canvas in the Ensemble window will jitter as it is animating. It appears to be jumping between two different positions each frame, as if the layout calculation returned a different answer each frame.

This is more noticeable on slower systems or when the SW pipeline is enabled. I have seen this on both Linux and Windows. I have not tried it on Mac, but I suspect it is platform-independent.

This is a regression. It works in the latest JDK 8u release and fails in JDK 9.