protected int addRows(final AbstractMemStore hmc) {
    return addRows(hmc, HConstants.LATEST_TIMESTAMP);
  }
Adds {@link #ROW_COUNT} rows and {@link #QUALIFIER_COUNT}
@param hmc Instance to add rows to.
@return How many rows we added.
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestDefaultMemStore.java