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
{
						sortKey = getColumnRefExpression(sortKey);
					}
					temporaryComputedColumns.add(new ComputedColumn( "_{$TEMP_SORT_"+i+"$}_", sortKey, DataType.ANY_TYPE));
					sortIndex = -1; 
					sortKey = String.valueOf("_{$TEMP_SORT_"+i+"$}_");
					
					IQuery.SortSpec dest = new IQuery.SortSpec( sortIndex,
							sortKey,
							src.getSortDirection( ) == ISortDefinition.SORT_ASC );
					sortSpecs[i] = dest;
				}
				odiQuery.setOrdering( Arrays.asList( sortSpecs));
			}
			
		    List dataSetFilters = new ArrayList( );
		    List queryFilters = new ArrayList( );
		    if ( dataSet.getFilters( ) != null )
			{
				dataSetFilters = dataSet.getFilters( );
			}
		    
		    if ( this.baseQueryDefn.getFilters( ) != null )
			{
		    	queryFilters = this.baseQueryDefn.getFilters( );
			}
		    
		    
		    List multipassFilters = prepareFilters( cx, dataSetFilters, queryFilters, temporaryComputedColumns );