Bug 195970 Two issues when evaluate a query inlcuding a subquery[07]
Description: Currently, when evaluating a query which includes a subquery, the query will be evaluated twice. The binding of query will pass to subquery twice. If user write a java script such as new Date() and i++. The result of query will be incorrect. Another issue: when write the report document, the binding of query will be written twice and the performance is not good to evalulate it twice.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/ResultIterator.java
* @param columnExprs
		 * @param i
		 * @return
		 * @throws BirtException
		 */
		private boolean groupKeyValuesEqual(
				org.eclipse.birt.data.engine.odi.IResultIterator odiResult,
				Object[] groupKeyValues, String[] columnExprs, int i )
				throws BirtException
		{
			Object fieldValue = null;
			
			try
			{
				Context cx = Context.enter( );
				fieldValue = ScriptEvalUtil.evalExpr( new ScriptExpression( columnExprs[i] ),
						cx,
						ResultIterator.this.scope,
						"Filter",
						0 );
				Context.exit( );
			}
			finally
			{
				Context.exit( );
			}
			boolean retValue = false;
			if ( fieldValue == groupKeyValues[i] )
			{
				retValue = true;