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/internal/navigator/actions/CommonActionProviderDescriptor.java
* 
	 * @param anElement
	 *            The element that should be used for the evaluation.
	 * @return True if and only if the extension is enabled for the element.
	 */
	public boolean isEnabledFor(Object anElement) {
		if (enablement == null || anElement == null) {
			return false;
		}
		IEvaluationContext context = NavigatorPlugin.getEvalContext(anElement);
		return NavigatorPlugin.safeEvaluate(enablement, context) == EvaluationResult.TRUE;
	}
	/**
	 * 
	 * @return An identifier for this ICommonActionProvider. Defaults to
	 *         "org.eclipse.ui.navigator.actionProvider". May not be unique.
	 *         Used to filter the actionProvider using the visibility state
	 *         information.
	 */
	public String getId() {
		return visibilityId;
	}
	/**
	 * 
	 * @return An identifier for this ICommonActionProvider. Defaults to
	 *         'org.eclipse.ui.navigator.actionProvider'. May not be unique.
	 *         Used to determine override or depends on cases.
	 */
	public String getDefinedId() {
		return definedId;