title: Create boolean tensor where values in one tensor are in another
body: <p>I want to find all the places where values from one tensor show up in another tensor. The output should be a Boolean tensor the same shape as the main tensor.</p>
  <pre><code>import numpy as np
  import tensorflow as tf
  
  values = np.random.randint(0, 32, (3, 32))
  check_vals = np.random.choice(values.flatten(), 2, False)
  
  main_tensor = tf.convert_to_tensor(values, dtype=tf.int32)
  check_tensor = tf.convert_to_tensor(check_vals, dtype=tf.int32)
  
  #In numpy I can just do this
  np_res = np.isin(values, check_vals)
  
  #and verify it worked by doing:
  print (check_vals)
  print (values[np_res])
  
  #How to do it in tensorflow??
  res = tf.equal(main_tensor, check_tensor)
  </code></pre>