message: Turn off layout optimizer (as with all other optimizers) in the memory
  optimizer test, because the test assumes no modification of the graph.
diff: @@ -128,6 +128,7 @@ class MemoryOptimizerRecomputeTest(test.TestCase):
  rewriter_config_pb2.RewriterConfig(
  disable_model_pruning=True,
  constant_folding=rewriter_config_pb2.RewriterConfig.OFF,
  + layout_optimizer=rewriter_config_pb2.RewriterConfig.OFF,
  arithmetic_optimization=rewriter_config_pb2.RewriterConfig.OFF,
  memory_optimization=rewriter_config_pb2.RewriterConfig.
  RECOMPUTATION_HEURISTICS), original_metagraph)
  @@ -151,6 +152,7 @@ class MemoryOptimizerRecomputeTest(test.TestCase):
  rewriter_config_pb2.RewriterConfig(
  disable_model_pruning=True,
  constant_folding=rewriter_config_pb2.RewriterConfig.OFF,
  + layout_optimizer=rewriter_config_pb2.RewriterConfig.OFF,
  arithmetic_optimization=rewriter_config_pb2.RewriterConfig.OFF,
  memory_optimization=rewriter_config_pb2.RewriterConfig.
  RECOMPUTATION_HEURISTICS,
  