Bug 263207 [CommonNavigator] Improve DnD tracing and add DnD test suite
There are no DnD tests for the Common Navigator. Also, the CNF has many test utility classes (basically stolen from JDT), these should be moved into a lower level area, and it looks like org.eclipse.ui.test.harness is a good place. (Perhaps we can get the JDT to use these identical versions as well so there is only one copy that everyone uses). Finally, the DnD tracing needs to be improved to show more information and show it more concisely.
tests/org.eclipse.ui.tests.navigator/src/org/eclipse/ui/tests/navigator/DisplayHelper.java
return events;
	}
	/**
	 * Until {@link #condition()} becomes <code>true</code> or the timeout
	 * elapses, call {@link Display#sleep()} and run the event loop.
	 * <p>
	 * If <code>timeout &lt; 0</code>, the event loop is never driven and
	 * only the condition is checked. If <code>timeout == 0</code>, the event
	 * loop is driven at most once, but <code>Display.sleep()</code> is never
	 * invoked.
	 * </p>
	 * <p>
	 * The condition gets rechecked every <code>interval</code> milliseconds, even
	 * if no events were read from the queue.
	 * </p>
	 * 
	 * @param display the display to run the event loop of
	 * @param timeout the timeout in milliseconds
	 * @param interval the interval to re-check the condition in milliseconds
	 * @return <code>true</code> if the condition became <code>true</code>,
	 *         <code>false</code> if the timeout elapsed
	 */
	public final boolean waitForCondition(Display display, long timeout, long interval) {
		
		if (condition())
			return true;
		
		if (timeout < 0)
			return false;