**Apache Airflow version**:

1.10.12

**What happened**:

I created dag with dagrun_timeout=2 minutes. 

After 2 minutes dagrun is marked as failed and the next one is started, but task keeps going.

**What you expected to happen**:

Task is killed with dag run as it is done when you mark dagrun failed manually.

**How to reproduce it**:
```
dag = DAG(dag_id='platform.airflow-test',
          description='',
          schedule_interval="0 0 * * *",
          start_date=datetime(2020, 7, 1),
          max_active_runs=1,
          catchup=True,
          dagrun_timeout=timedelta(minutes=2))

run_this = BashOperator(
    task_id='run_after_loop',
    bash_command=' for((i=1;i<=600;i+=1)); do echo "Welcome $i times"; sleep 1;  done',
    dag=dag,
)
```
tests/jobs/test_scheduler_job.py
"""
        Test that scheduler._create_dag_runs does not raise an error when the DAG does not exist
        in serialized_dag table
        """
        dag = DAG(dag_id='test_scheduler_create_dag_runs_does_not_raise_error', start_date=DEFAULT_DATE)
        DummyOperator(
            task_id='dummy',
            dag=dag,
        )
        dagbag = DagBag(
            dag_folder=os.devnull,
            include_examples=False,
            read_dags_from_db=False,
        )
        dagbag.bag_dag(dag=dag, root_dag=dag)
        
        DAG.bulk_write_to_db(dagbag.dags.values())
        dag_model = DagModel.get_dagmodel(dag.dag_id)
        scheduler = SchedulerJob(subdir=os.devnull, executor=self.null_exec)
        scheduler.processor_agent = mock.MagicMock()
        with create_session() as session, self.assertLogs(
            'airflow.jobs.scheduler_job', level="ERROR"
        ) as log_output:
            scheduler._create_dag_runs([dag_model], session)
            assert (
                "airflow.exceptions.SerializedDagNotFound: DAG "
                "'test_scheduler_create_dag_runs_does_not_raise_error' not found in serialized_dag table"
            ) in log_output.output[0]
    def test_bulk_write_to_db_external_trigger_dont_skip_scheduled_run(self):