SVG now processes results from the rasterizing thread on both the event
trigger and the core process events. In the test harness, this means
that either application.SendNotification, or
Test::WaitForEventThreadTrigger will complete the rasterizing task.
Added comment to remind testers about this timing, and moved the
test check prior to application.SendNotification.
Change-Id: If2d4298cd38af4f2c3c298f6010f321becfbdaf1