Bug 139346 Using isTopN in table inside list group header doesn't work.
Description: Using isTopN in table inside list group header doesn't work. Steps to reproduce: 1.Insert a list with a group 2.Insert a table to list group header 3.Using Total.isTopN(row[],2,null,0) as filter expression in table item. 4.Preview Result: Only the first group displayed top 2 records, other groups kept display all records.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/QueryExecutor.java
/**
	 * Create a new instance of data set runtime
	 * 
	 * @return
	 */
	abstract protected DataSetRuntime newDataSetRuntime( )
			throws DataException;
	
	/**
	 * Create a new unopened odiDataSource given the data source runtime
	 * definition
	 * 
	 * @return
	 */
	abstract protected IDataSource createOdiDataSource( )
			throws DataException;
	
	/**
	 * Create an empty instance of odi query
	 * 
	 * @return
	 */
	abstract protected IQuery createOdiQuery( ) throws DataException;
	
	/**
	 * Prepares the ODI query
	 */
	protected void prepareOdiQuery( ) throws DataException
	{
	}