**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
dr = dag.create_dagrun(
                run_type=DagRunType.SCHEDULED,
                execution_date=dag.following_schedule(dr.execution_date),
                state=State.RUNNING,
            )
        ex_date = dr.execution_date
        for tid, state in expected_task_states.items():
            if state != State.FAILED:
                continue
            self.null_exec.mock_task_fail(dag_id, tid, ex_date)
        try:
            dag = DagBag().get_dag(dag.dag_id)
            assert not isinstance(dag, SerializedDAG)
            
            dag.run(start_date=ex_date, end_date=ex_date, executor=self.null_exec, **run_kwargs)
        except AirflowException:
            pass
        
        for task_id, expected_state in expected_task_states.items():
            task = dag.get_task(task_id)
            ti = TaskInstance(task, ex_date)
            ti.refresh_from_db()
            assert ti.state == expected_state
        
        dr = DagRun.find(dag_id=dag_id, execution_date=ex_date)
        dr = dr[0]
        dr.dag = dag
        assert dr.state == dagrun_state
    def test_dagrun_fail(self):