Fix the mono test

Actually check that the reconfigured codec outputs the same data.
b/10095451

Change-Id: I367b410e1765ff126683e1ace5818ea72f5e8f32
diff --git a/tests/tests/media/src/android/media/cts/DecoderTest.java b/tests/tests/media/src/android/media/cts/DecoderTest.java
index 8fbee93..1e91c09 100644
--- a/tests/tests/media/src/android/media/cts/DecoderTest.java
+++ b/tests/tests/media/src/android/media/cts/DecoderTest.java
@@ -103,7 +103,6 @@
         short [] mono = decodeToMemory(res, false);
         if (mono.length == 44100) {
             // expected
-            return;
         } else if (mono.length == 88200) {
             // the decoder output 2 channels instead of 1, check that the left and right channel
             // are identical
@@ -116,7 +115,7 @@
 
         // we should get the same data when reconfiguring the codec
         short [] mono2 = decodeToMemory(res, true);
-        Arrays.equals(mono, mono2);
+        assertTrue(Arrays.equals(mono, mono2));
     }
 
     /**