message: doctest remove commas from array return
  fix yet another Ubuntu CPU test fail
diff: @@ -1909,9 +1909,9 @@ def grayscale_to_rgb(images, name=None):
  >>> original = tf.constant([[[1.0], [2.0], [3.0]]])
  >>> converted = tf.image.grayscale_to_rgb(original)
  >>> print(converted.numpy())
  - [[[1., 1., 1.],
  - [2., 2., 2.],
  - [3., 3., 3.]]]
  + [[[1. 1. 1.]
  + [2. 2. 2.]
  + [3. 3. 3.]]]
  ```
  