message: ipu_multi_worker_strategy_test: Fix global batch size in test
  Summary:
  Cherry-picked from the poplar/merge branch, where the rounding
  seems to have changed such that we got batches of sizes 1, 0
  on the different workers instead of 1, 1. Use the correct size.
  Reviewers: #tensorflow, davidn
diff: @@ -333,7 +333,7 @@ class IPUMultiWorkerStrategyTest(multi_worker_test_base.MultiWorkerTestBase):
  dataset = dataset_ops.Dataset.range(10)
  dataset = dataset.map(lambda x: math_ops.cast(x, np.float32))
  - dataset = dataset.batch(1, drop_remainder=True)
  + dataset = dataset.batch(2, drop_remainder=True) # global batch size
  dist_dataset = strategy.experimental_distribute_dataset(dataset)
  inputs = dist_dataset.make_initializable_iterator()
  per_replica_y = strategy.experimental_run_v2(step_fn, args=[next(inputs)])
  