@Override
    protected void chore() {
      try {
        persistRegionLastFlushedSequenceIds();
      } catch (IOException e) {
        LOG.debug("Failed to persist last flushed sequence id of regions" + " to file system", e);
      }
    }
Regions may have been removed between latest persist of FlushedSequenceIds and master abort. So
after loading FlushedSequenceIds from file, and after meta loaded, we need to remove the
deleted region according to RegionStates.
hbase-server/src/main/java/org/apache/hadoop/hbase/master/ServerManager.java