[ColorPicker, RTL] On color palette, arrow keys don't work well in RTL orientation.

JavaFX 8u40 b14. It's a regression from b13, might be caused by the fix of RT-39246.
Steps to reproduce the problem:
1. Run an application containing a ColorPicker, and set node orientation to RTL.
2. Open the color palette
3. Press arrow keys on the palette.

RIGHT and LEFT arrow keys don't work when the focus is placed at both ends of the rows.