message: Convert the iterator into a list in python3
  Summary:
  Python3 (.6?) produces an iterator from 'range', while the
  tensorflow API requires a list.
  Test Plan: existing tests
  Reviewers: georgep
diff: @@ -72,7 +72,7 @@ class IpuXlaTensorArrayTest(test_util.TensorFlowTestCase):
  tb = tb.write(2, ta.read(2) + in2)
  tb = tb.write(3, ta.read(3) + in2)
  tb = tb.write(4, ta.read(4) + in2)
  - out = tb.gather(range(4))
  + out = tb.gather(list(range(4)))
  v = session.run(out, feed_dict={in1: [[1,1],[2,2],[3,3],[4,4],[5,5]],
  in2: [1,1]})
  