Cut down the SVG test times by half

All the tests in the patch wait unnecessarily for another 100ms
when the animation runs for less than 100ms.
The comment in the tests mentions waiting another 100ms for repaint
but in actual the repaint times are few milli secs.

BUG=262332

Review URL: https://chromiumcodereview.appspot.com/19822008

git-svn-id: svn://svn.chromium.org/blink/trunk@154821 bbb929c8-8fbe-4397-9dbb-9b2b20218538