reduce epoch (#27661)

python/paddle/fluid/tests/unittests/test_fleet_graph_executor.py

@@ -76,7 +76,7 @@ class TestFleetGraphExecutionMetaOptimizer(unittest.TestCase):
                         2, size=(128, 1)).astype('int64')
                 }
 
-            for i in range(10):
+            for i in range(5):
                 cost_val = exe.run(feed=gen_data(), fetch_list=[avg_cost.name])
                 print("cost of step[{}] = {}".format(i, cost_val))