**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
)
        BashOperator(task_id='dummy1', dag=dag, owner='airflow', bash_command='echo hi')
        BashOperator(task_id='dummy2', dag=dag, owner='airflow', bash_command='echo hi')
        with create_session() as session:
            orm_dag = DagModel(dag_id=dag.dag_id)
            session.merge(orm_dag)
        dag = SerializedDAG.from_dict(SerializedDAG.to_dict(dag))
        scheduler = SchedulerJob(subdir=os.devnull)
        scheduler.processor_agent = mock.MagicMock()
        scheduler.dagbag.bag_dag(dag, root_dag=dag)
        dag.clear()
        dr = dag.create_dagrun(
            run_type=DagRunType.SCHEDULED,
            execution_date=DEFAULT_DATE,
            state=State.RUNNING,
        )
        assert dr is not None
        with create_session() as session:
            tis = dr.get_task_instances(session=session)
            for ti in tis:
                ti.state = state
                ti.start_date = start_date
                ti.end_date = end_date
            count = scheduler._schedule_dag_run(dr, set(), session)
            assert count == 2
            session.refresh(tis[0])
            session.refresh(tis[1])
            assert tis[0].state == State.SCHEDULED
            assert tis[1].state == State.SCHEDULED
    def test_scheduler_job_add_new_task(self):