MediaPlayerTest.testGetTrackInfo: fix effect-less statement

Change-Id: I5e836670435077de364f3788043c96f109c798fc
diff --git a/tests/tests/media/src/android/media/cts/MediaPlayerTest.java b/tests/tests/media/src/android/media/cts/MediaPlayerTest.java
index 275a648..0817c65 100644
--- a/tests/tests/media/src/android/media/cts/MediaPlayerTest.java
+++ b/tests/tests/media/src/android/media/cts/MediaPlayerTest.java
@@ -1063,7 +1063,7 @@
             if (trackInfos[i].getTrackType() == MediaPlayer.TrackInfo.MEDIA_TRACK_TYPE_TIMEDTEXT) {
                 String trackLanguage = trackInfos[i].getLanguage();
                 assertTrue(trackLanguage != null);
-                trackLanguage.trim();
+                trackLanguage = trackLanguage.trim();
                 Log.d(LOG_TAG, "track info lang: " + trackLanguage);
                 assertTrue("Should not see empty track language with our test data.",
                            trackLanguage.length() > 0);