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/LabelProviderTest.java
_contentService.bindExtensions(new String[] { TEST_CONTENT_OVERRIDDEN1,
				TEST_CONTENT_OVERRIDE1 }, false);
		_contentService.getActivationService()
				.activateExtensions(
						new String[] { TEST_CONTENT_OVERRIDE1,
								TEST_CONTENT_OVERRIDDEN1 }, true);
		refreshViewer();
		TreeItem[] rootItems = _viewer.getTree().getItems();
		checkItemsAll(rootItems, TestLabelProviderStyledGreen.instance);
	}
	/**
	 * E{low} overrides D{low} overrides B{normal} overrides A F{high} overrides
	 * C{low} overrides A G{normal} overrides C{low} B branch has higher
	 * priority than C's, and G higher than G, so order should be B branch (E -
	 * D - B) then C branches (F - G - C) then A
	 */
	public void testOverrideChain() throws Exception {
		final String[] EXTENSIONS = new String[] {
				TEST_CONTENT_TRACKING_LABEL + ".A",
				TEST_CONTENT_TRACKING_LABEL + ".B",
				TEST_CONTENT_TRACKING_LABEL + ".C",
				TEST_CONTENT_TRACKING_LABEL + ".D",
				TEST_CONTENT_TRACKING_LABEL + ".E",
				TEST_CONTENT_TRACKING_LABEL + ".F",
				TEST_CONTENT_TRACKING_LABEL + ".G" };
		_contentService.bindExtensions(EXTENSIONS, true);
		_contentService.getActivationService().activateExtensions(EXTENSIONS,
				true);
		refreshViewer();
		_viewer.getTree().getItems();