In both tests the scrolled actor's width was fixed to the stage
width, so that the scroll bars ended up outside the visible area.
Fix by adding an outer container with a fixed width and expanding
the scroll view to fill the available area.
Non-uniform border-radii are already supported when using a gradient
background, this patch adds support for solid colors as well.
The currently applied technique of using corner textures and filling
the remaining area with rectangles is extended, so that each corner is
padded with rectangles to the size of the largest corner.
Add border-radius.js to test cases, to test non-uniform border-radii
with both solid color and gradient backgrounds.
https://bugzilla.gnome.org/show_bug.cgi?id=631091
