**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
dag_file = os.path.join(
            os.path.dirname(os.path.realpath(__file__)), '../dags/test_only_dummy_tasks.py'
        )
        
        dagbag = DagBag(dag_folder=dag_file, include_examples=False, read_dags_from_db=False)
        dagbag.sync_to_db()
        scheduler_job = SchedulerJob(subdir=os.devnull)
        scheduler_job.processor_agent = mock.MagicMock()
        dag = scheduler_job.dagbag.get_dag("test_only_dummy_tasks")
        
        session = settings.Session()
        orm_dag = session.query(DagModel).get(dag.dag_id)
        scheduler_job._create_dag_runs([orm_dag], session)
        drs = DagRun.find(dag_id=dag.dag_id, session=session)
        assert len(drs) == 1
        dr = drs[0]
        
        scheduler_job._schedule_dag_run(dr, {}, session)
        with create_session() as session:
            tis = session.query(TaskInstance).all()
        dags = scheduler_job.dagbag.dags.values()
        assert ['test_only_dummy_tasks'] == [dag.dag_id for dag in dags]
        assert 5 == len(tis)
        assert {
            ('test_task_a', 'success'),
            ('test_task_b', None),
            ('test_task_c', 'success'),
            ('test_task_on_execute', 'scheduled'),
            ('test_task_on_success', 'scheduled'),