Bug 299340 [CommonNavigator] Enable new CNF tests
Enable the contributed CNF tests, make minor test improvements.
tests/org.eclipse.ui.tests.navigator/src/org/eclipse/ui/tests/navigator/M12Tests.java
TreeItem[] rootItems = _viewer.getTree().getItems();
		
		_expand(rootItems);
		IFolder newFolder1 = _p1.getFolder(NEW_FOLDER_1);
		newFolder1.create(true, true, new NullProgressMonitor());
		TreeItem folder1Item = _findChild(NEW_FOLDER_1, rootItems[_p1Ind]
				.getItems());
		assertNotNull("M1 interceptAdd method should have been called",
				folder1Item);
	}
	/**
	 * Verifies that M1 interceptRemove is called when the resourceContent
	 * provider invokes viewer.remove(IResource). Currently fails in Ganymede
	 * and Galileo due to defect #285529.
	 * 
	 * @throws CoreException
	 */
	
	public void testInterceptRemove() throws CoreException {
		final String NEW_FOLDER_1 = "newFolder1";
		_initContent();
		TreeItem[] rootItems = _viewer.getTree().getItems();
		
		_expand(rootItems);
		IFolder newFolder1 = _p1.getFolder(NEW_FOLDER_1);
		if (!newFolder1.exists()) {
			newFolder1.create(true, true, new NullProgressMonitor());
		}
		TreeItem folder1Item = _findChild(NEW_FOLDER_1, rootItems[_p1Ind]
				.getItems());