message: Remove enable collective ops tests
  We now have multi worker unit tests so these are already covered. We should test
  the API, not the implementation.
diff: @@ -400,48 +400,6 @@ class DistributedCollectiveAllReduceStrategyTest(
  self.assertEqual(['CollectiveReduce'],
  new_rewrite_options.scoped_allocator_opts.enable_op)
  - def _get_strategy_with_mocked_methods(self):
  - mock_called = [False]
  -
  - # pylint: disable=dangerous-default-value
  - def mock_enable_collective_ops(server_def, mock_called=mock_called):
  - self.assertEqual('worker', server_def.job_name)
  - self.assertEqual(1, server_def.task_index)
  - self.assertEqual('grpc', server_def.protocol)
  - mock_called[0] = True
  -
  - def mock_configure_collective_ops(*args, **kwargs):
  - del args, kwargs
  -
  - with test.mock.patch.object(context.context(), 'enable_collective_ops',
  - mock_enable_collective_ops), \
  - test.mock.patch.object(context.context(), 'configure_collective_ops',
  - mock_configure_collective_ops):
  - strategy, _, _ = self._get_test_object(
  - task_type='worker', task_id=1, num_gpus=2)
  -
  - return strategy, mock_called
  -
  - @combinations.generate(combinations.combine(mode=['eager']))
  - def testEnableCollectiveOps(self):
  - # We cannot enable check health with this test because it mocks
  - # enable_collective_ops.
  - CollectiveAllReduceExtended._enable_check_health = False
  - strategy, mock_called = self._get_strategy_with_mocked_methods()
  - CollectiveAllReduceExtended._enable_check_health = True
  - self.assertTrue(strategy.extended._std_server_started)
  - self.assertTrue(mock_called[0])
  -
  - @combinations.generate(combinations.combine(mode=['eager']))
  - def testEnableCollectiveOpsAndClusterResolver(self):
  - # We cannot enable check health with this test because it mocks
  - # enable_collective_ops.
  - CollectiveAllReduceExtended._enable_check_health = False
  - strategy, _ = self._get_strategy_with_mocked_methods()
  - CollectiveAllReduceExtended._enable_check_health = True
  - self.assertEqual(strategy.cluster_resolver.task_type, 'worker')
  - self.assertEqual(strategy.cluster_resolver.task_id, 1)
  -
  class DistributedCollectiveAllReduceStrategyTestWithChief(
  CollectiveAllReduceStrategyTestBase, parameterized.TestCase):
  