enable delay op feature

Author: chengduoZH

paddle/fluid/framework/details/threaded_ssa_graph_executor.cc

@@ -128,7 +128,7 @@ FeedFetchList ThreadedSSAGraphExecutor::Run(
     //
     // NOTE: DelayedOps have a lower priority. It will be scheduled after all
     // ready_ops have been performed.
-    if (ready_ops.empty() && allow_op_delay_) {
+    if (ready_ops.empty() && allow_op_delay_ && running_ops_ == 0) {
       run_all_ops(delayed_ops);
     } else {
       run_all_ops(ready_ops);