Uncomment a test that was marked as STOPSHIP

Add MediumTest tag

Change-Id: I0699d168d7ec70c076f4713e0e405c0779a290c6

Author: Suchi Amalapurapu

core/tests/coretests/src/android/content/pm/PackageManagerTests.java

@@ -1039,10 +1039,9 @@ private boolean mountFromRawResource() {
      * Install package on sdcard. Unmount and then mount the media.
      * (Use PackageManagerService private api for now)
      * Make sure the installed package is available.
-     * STOPSHIP will uncomment when MountService api's to mount/unmount
-     * are made asynchronous.
      */
-    public void xxxtestMountSdNormalInternal() {
+    @MediumTest
+    public void testMountSdNormalInternal() {
         assertTrue(mountFromRawResource());
     }