message: Add existing function_def attributes to the created ConcreteFunction during load.
  Exclude the "_input_shapes" attribute, which may cause an error during input shape initialization later.
diff: @@ -366,7 +366,12 @@ def load_function_def_library(library, load_shared_name_suffix=None):
  # signatures, respectively). ConcreteFunction that are part of a saved
  # function is set up later by recreate_function(); and bare ConcreteFunction
  # is set up by by setup_bare_concrete_function().
  - func = function_lib.ConcreteFunction(func_graph)
  + # However, we copy the FunctionDef attributes to the new ConcreteFunction,
  + # excluding the "_input_shapes", which may cause an error during input shape
  + # initialization at a later stage.
  + if "_input_shapes" in copy.attr:
  + del copy.attr["_input_shapes"]
  + func = function_lib.ConcreteFunction(func_graph, attrs=copy.attr)
  func.add_to_graph(graph)
  functions[fdef.signature.name] = func
  