function clearPendingUIUpdates(clock) {
		return nextUIUpdate(clock);
	}
In some tests that are using fake timers, it might happen that a rendering task is queued by
creating a fake timer. Without an appropriate clock.tick call, this timer might not execute
and a later nextUIUpdate with real timers would wait endlessly.
To prevent this, after each such test a sync rendering is executed which will clear any pending
fake timer. The rendering itself should not be needed by the tests, if they are properly
isolated.

This function is used as an indicator for such cases. It's just a wrapper around nextUIUpdate.