CSSParser fails for items in a sequence of Paints after a radial gradient.

The following CSS value causes an NPE, caused by the last value in the sequence becoming null.

    -fx-background-color:
        rgb(57, 117, 239),
        radial focus-angle 0.05 center (50%, 0%) 30.43% stops (0%, white) (33%, white) (100%, transparent),
        radial focus-angle -0.03 center (50%, 100%) 21% stops (0%, white) (13%, white) (100%, transparent);