**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 to check that a DAG returns its active runs
        """
        now = timezone.utcnow()
        six_hours_ago_to_the_hour = (now - datetime.timedelta(hours=6)).replace(
            minute=0, second=0, microsecond=0
        )
        start_date = six_hours_ago_to_the_hour
        dag_name1 = 'get_active_runs_test'
        default_args = {'owner': 'airflow', 'depends_on_past': False, 'start_date': start_date}
        dag1 = DAG(dag_name1, schedule_interval='* * * * *', max_active_runs=1, default_args=default_args)
        run_this_1 = DummyOperator(task_id='run_this_1', dag=dag1)
        run_this_2 = DummyOperator(task_id='run_this_2', dag=dag1)
        run_this_2.set_upstream(run_this_1)
        run_this_3 = DummyOperator(task_id='run_this_3', dag=dag1)
        run_this_3.set_upstream(run_this_2)
        session = settings.Session()
        orm_dag = DagModel(dag_id=dag1.dag_id)
        session.merge(orm_dag)
        session.commit()
        session.close()
        dag1.clear()
        dr = dag1.create_dagrun(
            run_type=DagRunType.SCHEDULED,
            execution_date=start_date,