message: Disable constant folding for the tf.dbg test, as it makes assumptions on the
  underlying graph structure.
diff: @@ -55,7 +55,8 @@ class StepperTest(test_util.TensorFlowTestCase):
  self.z = math_ops.multiply(self.x, self.y, name="z") # Should be -4.0.
  rewriter_config = rewriter_config_pb2.RewriterConfig(
  - disable_model_pruning=True)
  + disable_model_pruning=True,
  + constant_folding=rewriter_config_pb2.RewriterConfig.OFF)
  graph_options = config_pb2.GraphOptions(rewrite_options=rewriter_config)
  config = config_pb2.ConfigProto(graph_options=graph_options)
  self.sess = session.Session(config=config)
  @@ -588,7 +589,8 @@ class StepperAssignAddTest(test_util.TensorFlowTestCase):
  name="v_add_plus_one")
  rewriter_config = rewriter_config_pb2.RewriterConfig(
  - disable_model_pruning=True)
  + disable_model_pruning=True,
  + constant_folding=rewriter_config_pb2.RewriterConfig.OFF)
  graph_options = config_pb2.GraphOptions(rewrite_options=rewriter_config)
  config = config_pb2.ConfigProto(graph_options=graph_options)
  self.sess = session.Session(config=config)
  @@ -719,7 +721,8 @@ class StepperBackwardRunTest(test_util.TensorFlowTestCase):
  self.f, name="optim")
  rewriter_config = rewriter_config_pb2.RewriterConfig(
  - disable_model_pruning=True)
  + disable_model_pruning=True,
  + constant_folding=rewriter_config_pb2.RewriterConfig.OFF)
  graph_options = config_pb2.GraphOptions(rewrite_options=rewriter_config)
  config = config_pb2.ConfigProto(graph_options=graph_options)
  self.sess = session.Session(config=config)
  