@Override
  public void addWriteIdsToMinHistory(QueryPlan plan, ValidTxnWriteIdList txnWriteIds) {
    
  }
Dedup the list of lock objects so that there is only one lock per table/partition.
If there is both a shared and exclusive lock for the same object, this will deduped
to just a single exclusive lock.  Package level so that the unit tests
can access it.  Not intended for use outside this class.
@param lockObjects
ql/src/java/org/apache/hadoop/hive/ql/lockmgr/DummyTxnManager.java