Tests the discard element with unsupported values for the 'begin' attribute.
Three red rects should be discarded after 0s, since their 'begin' attribute
values are unsupported. A blue circle with animated radius indicates by
turning green that the radius-animation has been repeated. This is to verify
that the discard with id="discard1" does not wait until the circle-animation
has looped once before it discards its target.
The test has passed if after 5 seconds there is nothing red visible, and
there are four green circles visible.
