Workaround/Fix #3351

1. Ignore edit list where the sequence doesn't contain a sync
   sample, rather than failing.
2. Make Mp4Extractor.readAtomPayload so it doesn't try and read
   the same payload twice if a failure occurs parsing it.
3. Make processAtomEnded so that it doesn't pop the moov if
   parsing it fails.

Issue: #3351

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=172106244

library/core/src/main/java/com/google/android/exoplayer2/extractor/mp4/AtomParsers.java

@@ -395,7 +395,11 @@ import java.util.List;
       hasSyncSample |= (editedFlags[i] & C.BUFFER_FLAG_KEY_FRAME) != 0;
       hasSyncSample |= (editedFlags[i] & C.BUFFER_FLAG_KEY_FRAME) != 0;
     }
     }
     if (!hasSyncSample) {
     if (!hasSyncSample) {
-      throw new ParserException("The edited sample sequence does not contain a sync sample.");
+      // We don't support edit lists where the edited sample sequence doesn't contain a sync sample.
+      // Such edit lists are often (although not always) broken, so we ignore it and continue.
+      Log.w(TAG, "Ignoring edit list: Edited sample sequence does not contain a sync sample.");
+      Util.scaleLargeTimestampsInPlace(timestamps, C.MICROS_PER_SECOND, track.timescale);
+      return new TrackSampleTable(offsets, sizes, maximumSize, timestamps, flags);
     }
     }
 
 
     return new TrackSampleTable(editedOffsets, editedSizes, editedMaximumSize, editedTimestamps,
     return new TrackSampleTable(editedOffsets, editedSizes, editedMaximumSize, editedTimestamps,