Merge pull request #15575 from JiabinYang/feature/imperative

test=develop, polish code and fix some wrong change

paddle/fluid/inference/utils/CMakeLists.txt

 cc_library(benchmark SRCS benchmark.cc DEPS enforce)
 cc_test(test_benchmark SRCS benchmark_tester.cc DEPS benchmark)
-#cc_binary(visualizer SRCS visualizer.cc DEPS analysis
-#    paddle_pass_builder ir_pass_manager pass graph_viz_pass analysis_passes)
+cc_binary(visualizer SRCS visualizer.cc DEPS analysis
+    paddle_pass_builder ir_pass_manager pass graph_viz_pass analysis_passes)

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

@@ -268,9 +268,6 @@ class TestImperativePtbRnn(unittest.TestCase):
                 sgd.minimize(dy_loss)
                 for param in ptb_model.parameters():
                     dy_param_updated[param.name] = param._numpy()
-                # print("dy_loss is {}".format(dy_loss._numpy()))
-                # print("last_hidden is {}".format(last_hidden._numpy()))
-                # print("last_cell is {}".format(last_cell._numpy()))
 
         with new_program_scope():
             fluid.default_startup_program().random_seed = seed