WPT tests are expected to create screenshots as soon as everything is
loaded. If an animation is happening adding the "reftest-wait" class to
the root element is appropriate way to delay the screenshot. Previously,
the
test harness was waiting for all animations to finish, but that is just
leading to many timeouts. Removing that code fixes the timeouts.
Two Servo-specific tests are also updated as they were written with
Servo's previous behavior in mind.
Testing: There are test result updates for this change. Many TIMEOUTS
now either correctly
PASS OR FAIL.
Fixes: #36931.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
