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**Description**

Related to the discussion here: https://github.com/apache/airflow/pull/8553#discussion_r416136954

Allow user to define expected terminal state. e.g. `JOB_STATE_CANCELLED` could be not treated as failure but expected terminal state.


<!-- A short description of your feature -->


@mock.patch("airflow.providers.google.cloud.operators.dataflow.DataflowHook")
    def test_exec_job_id(self, dataflow_mock):
        self.dataflow = DataflowStopJobOperator(
            task_id=TASK_ID,
            project_id=TEST_PROJECT,
            job_id=JOB_ID,
            poll_sleep=POLL_SLEEP,
            location=TEST_LOCATION,
        )
        """
        Test DataflowHook is created and the right args are passed to cancel_job.
        """
        cancel_job_hook = dataflow_mock.return_value.cancel_job
        self.dataflow.execute(None)
        assert dataflow_mock.called
        cancel_job_hook.assert_called_once_with(
            job_name=None,
            project_id=TEST_PROJECT,
            location=TEST_LOCATION,
            job_id=JOB_ID,
        )
    @mock.patch("airflow.providers.google.cloud.operators.dataflow.DataflowHook")
    def test_exec_job_name_prefix(self, dataflow_mock):