public long getTotalSeconds(int elementNum) {
    return totalSeconds[elementNum];
  }
Return a row's HiveIntervalDayTime.getTotalSeconds() value.
We assume the entry has already been NULL checked and isRepeated adjusted.
@param elementNum
@return
storage-api/src/java/org/apache/hadoop/hive/ql/exec/vector/IntervalDayTimeColumnVector.java