Always use cloudpickle instead of cloudpickle_fast, even in Python 3.8+.

PiperOrigin-RevId: 311330869

Author: jburnim

tensorflow_probability/python/layers/distribution_layer.py

@@ -25,7 +25,7 @@
 import pickle
 
 # Dependency imports
-from cloudpickle import CloudPickler
+from cloudpickle.cloudpickle import CloudPickler
 import numpy as np
 import six
 import tensorflow.compat.v2 as tf