fix parallel sequence

Author: zhangwenchao-123

src/backend/gpopt/translate/CTranslatorDXLToPlStmt.cpp

@@ -5149,6 +5149,7 @@ CTranslatorDXLToPlStmt::TranslateDXLParallelSequence(
 	Plan *plan = &(psequence->plan);
 	plan->plan_node_id = m_dxl_to_plstmt_context->GetNextPlanId();
 
+	plan->parallel_aware = true;
 	plan->parallel_safe = true;
 	plan->parallel = (int) parallel_workers;