fix ut. test=develop

Author: zmxdream

python/paddle/distributed/fleet/base/fleet_base.py

@@ -692,7 +692,7 @@ def load_model(self, path, mode):
 
     @is_non_distributed_check
     @inited_runtime_handler
-    def run_heter_worker(self, dataset=None):
+    def run_heter_worker(self, dataset):
         """
         run_heter_worker will run heter trainer main program with executor.
 

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

@@ -194,7 +194,7 @@ def do_dataset_heter_training(self, fleet):
         batch_size = 128
 
         pass_start = time.time()
-        fleet.run_heter_worker()
+        fleet.run_heter_worker(dataset=None)
         pass_time = time.time() - pass_start
         print("do_dataset_heter_training done. using time {}".format(pass_time))