message: Fix spelling/typo.
diff: @@ -59,7 +59,7 @@ _UPDATE_GOLDENS_HELP = """
  # DEFINE_boolean, only_test_core_api, default False:
  _ONLY_TEST_CORE_API_HELP = """
  Some TF APIs are being moved outside of the tensorflow/ directory. There is
  - no garuntee which versions of these APIs will be present when running this
  + no guarantee which versions of these APIs will be present when running this
  test. Therefore, do not error out on API changes in non-core TF code
  if this flag is set.
  """
  