Fix NPE when bundle is not started

Currently the code checks for 'localizationTracker == null' to see if
bundle is started, but that field is actually never null (as it is a
final field always initilized with a value) instead the Activator
instance itself can be null.

This changes the method to replace the usless check with one that checks
if the activator instance is null and additionally make the method
static.

bundles/org.eclipse.equinox.common/src/org/eclipse/core/internal/runtime/Activator.java

@@ -197,11 +197,13 @@ public String getBundleId(Object object) {
 	 * in the given locale. Does not return null.
 	 * @throws MissingResourceException If the corresponding resource could not be found
 	 */
-	public ResourceBundle getLocalization(Bundle bundle, String locale) throws MissingResourceException {
-		if (localizationTracker == null) {
-			throw new MissingResourceException(CommonMessages.activator_resourceBundleNotStarted, bundle.getSymbolicName(), ""); //$NON-NLS-1$
+	public static ResourceBundle getLocalization(Bundle bundle, String locale) throws MissingResourceException {
+		Activator activator = Activator.getDefault();
+		if (activator == null) {
+			throw new MissingResourceException(CommonMessages.activator_resourceBundleNotStarted,
+					bundle.getSymbolicName(), ""); //$NON-NLS-1$
 		}
-		BundleLocalization location = localizationTracker.current().orElse(null);
+		BundleLocalization location = activator.localizationTracker.current().orElse(null);
 		ResourceBundle result = null;
 		if (location != null)
 			result = location.getLocalization(bundle, locale);

bundles/org.eclipse.equinox.common/src/org/eclipse/core/internal/runtime/ResourceTranslator.java

@@ -70,7 +70,7 @@ private static ResourceBundle getResourceBundle(Bundle bundle, String language)
 			Locale locale = (language == null) ? Locale.getDefault() : new Locale(language);
 			return ResourceBundle.getBundle("plugin", locale, createTempClassloader(bundle)); //$NON-NLS-1$
 		}
-		return Activator.getDefault().getLocalization(bundle, language);
+		return Activator.getLocalization(bundle, language);
 	}
 
 	public static String[] getResourceString(Bundle bundle, String[] nonTranslated, String locale) {