Fix ID3 EOS detection for two-byte encodings

Issue: #1774

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=131389528

library/src/main/java/com/google/android/exoplayer2/metadata/id3/Id3Decoder.java

@@ -98,7 +98,7 @@ private static int indexOfEos(byte[] data, int fromIndex, int encoding) {
 
     // Otherwise look for a second zero byte.
     while (terminationPos < data.length - 1) {
-      if (data[terminationPos + 1] == (byte) 0) {
+      if (terminationPos % 2 == 0 && data[terminationPos + 1] == (byte) 0) {
         return terminationPos;
       }
       terminationPos = indexOfZeroByte(data, terminationPos + 1);