Bug 132805 Set descending to outer group will affect inner group.
Description: Set descending to outer group will affect inner group. Steps to reproduce: 1. New a sample datasource and dataset from orders. 2. Drag the dataset to Layout. 3. Add a group on ordernumber, interval 10, descending. 4. Add another group on orderdate, interval day 2, ascending. 5. Preview. Expected result: Data are grouped correctly. Actual result: Inner group didn't work unless you set outer group's sort to asc.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/QueryExecutor.java
OnFetchScriptHelper event = new OnFetchScriptHelper( dataSet ); 
	    		odiQuery.addOnFetchEvent( event );
		    }
	    	
		    if ( dataSetFilters.size( ) + queryFilters.size( ) + multipassFilters.size() > 0 )
		    {
		    	IResultObjectEvent objectEvent = new FilterByRow( dataSetFilters, queryFilters, multipassFilters,
		    			dataSet );
		    	odiQuery.addOnFetchEvent( objectEvent );
		    }
		    
			
		    odiQuery.setMaxRows( this.baseQueryDefn.getMaxRows() );
		}
		finally
		{
			Context.exit();
		}
	}
	/**
	 * 
	 * @param expr
	 * @return
	 */
	private String getColumnRefExpression(String expr) 
	{
		return "row[\""+ expr + "\"]";
	}
	
	void setParentExecutorHelper( IExecutorHelper helper )