Bug 139986 [CommonNavigator] Convert catch(Error/Throwable) to SafeRunner
In several places the CN framework uses catch(Error/Throwable) to ensure that code does not bring the framework down. Change these to use SafeRunner.
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/navigator/CommonNavigator.java
* @nooverride This method is not intended to be re-implemented or extended by clients.
	 * @since 3.4
	 */
	public int getRootMode() {
		
		return 0;
	}
	/**
	 * @param label
	 * @noreference This method is not intended to be referenced by clients.
	 * @nooverride This method is not intended to be re-implemented or extended by clients.
	 * @since 3.4
	 */
	public void setWorkingSetLabel(String label) {
		
	}
	/**
	 * @return the working set label
	 * @noreference This method is not intended to be referenced by clients.
	 * @nooverride This method is not intended to be re-implemented or extended by clients.
	 * @since 3.4
	 */
	public String getWorkingSetLabel() {
		
		return null;
	}
	
	
}