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/EditorTestHelper.java
IWorkbenchWindow window= getActiveWorkbenchWindow();
		if (window != null)
			runEventQueue(window.getShell());
	}
	
	public static void runEventQueue(IWorkbenchPart part) {
		runEventQueue(part.getSite().getShell());
	}
	
	public static void runEventQueue(Shell shell) {
		runEventQueue(shell.getDisplay());
	}
	
	public static void runEventQueue(Display display) {
		while (display.readAndDispatch()) {
			
		}
	}
	
	/**
	 * Runs the event queue on the current display and lets it sleep until the
	 * timeout elapses.
	 * 
	 * @param millis the timeout in milliseconds
	 */
	public static void runEventQueue(long millis) {
		runEventQueue(getActiveDisplay(), millis);
	}
	
	public static void runEventQueue(IWorkbenchPart part, long millis) {