Revert "[Settings] Support getSystemService(Class<T>)"

This reverts commit d5ccde31a8.

Reason for revert: failure on test cases

Change-Id: I0a179a6ebb5ef1dec566ce6e8facd5f3b82d7c8a

src/com/android/settings/wifi/ConfigureWifiSettings.java

@@ -69,7 +69,7 @@ public class ConfigureWifiSettings extends DashboardFragment {
 
     @Override
     protected List<AbstractPreferenceController> createPreferenceControllers(Context context) {
-        final WifiManager wifiManager = getSystemService(WifiManager.class);
+        final WifiManager wifiManager = (WifiManager) getSystemService(WIFI_SERVICE);
         final List<AbstractPreferenceController> controllers = new ArrayList<>();
         controllers.add(new WifiP2pPreferenceController(context, getSettingsLifecycle(),
                 wifiManager));