message: Fix pipeline test
  Summary:
  Ref T21406
  no-cherry-pick
  Reviewers: #tensorflow, #framework_ip_review_-_any_oss_or_third-party_code_use_has_been_approved, jakeh, davidn
  Maniphest Tasks: T21406
diff: @@ -98,14 +98,13 @@ class PipeliningRecomputationConvClassifyTest(test_util.TensorFlowTestCase):
  x = array_ops.placeholder(np.float32, shape=[1, 224])
  l = array_ops.placeholder(np.int32, shape=[1])
  + with tu.ipu_session() as sess:
  +
  with ops.device("/device:IPU:0"):
  compiled_model_pipeline = ipu_compiler.compile(model_pipeline,
  inputs=[x, l])
  -
  - tu.move_variable_initialization_to_cpu()
  outfeed_queue.dequeue()
  -
  - with tu.ipu_session() as sess:
  + tu.move_variable_initialization_to_cpu()
  report = tu.ReportJSON(self, sess, pipelining=True, allow_recompute=True)
  sess.run(variables.global_variables_initializer())
  @@ -161,14 +160,13 @@ class PipeliningRecomputationConvClassifyTest(test_util.TensorFlowTestCase):
  x = array_ops.placeholder(np.float32, shape=[1, 224])
  l = array_ops.placeholder(np.int32, shape=[1])
  + with tu.ipu_session() as sess:
  +
  with ops.device("/device:IPU:0"):
  compiled_model_pipeline = ipu_compiler.compile(model_pipeline,
  inputs=[x, l])
  -
  - tu.move_variable_initialization_to_cpu()
  outfeed_queue.dequeue()
  -
  - with tu.ipu_session() as sess:
  + tu.move_variable_initialization_to_cpu()
  report = tu.ReportJSON(self, sess, pipelining=True, allow_recompute=True)
  sess.run(variables.global_variables_initializer())
  