message: Fix test_session warnings during tests by replacing it with session()
diff: @@ -164,7 +164,7 @@ class QuantileOpsTest(test_util.TensorFlowTestCase):
  self.assertAllClose(self._feature_1_boundaries, buckets[1].eval())
  save.save(sess, save_path)
  - with self.test_session(graph=ops.Graph()) as sess:
  + with self.session(graph=ops.Graph()) as sess:
  accumulator = boosted_trees_ops.QuantileAccumulator(
  num_streams=2, num_quantiles=3, epsilon=self.eps, name="q0")
  save = saver.Saver()
  @@ -195,7 +195,7 @@ class QuantileOpsTest(test_util.TensorFlowTestCase):
  self.assertAllClose(self._feature_0_boundaries, buckets[0].eval())
  self.assertAllClose(self._feature_1_boundaries, buckets[1].eval())
  - with self.test_session(graph=ops.Graph()) as sess:
  + with self.session(graph=ops.Graph()) as sess:
  accumulator = boosted_trees_ops.QuantileAccumulator(
  num_streams=2, num_quantiles=3, epsilon=self.eps, name="q0")
  save = saver.Saver()
  