**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
other_dag = self.dagbag.get_dag('test_task_start_date_scheduling')
            other_dag.is_paused_upon_creation = True
            other_dag.sync_to_db()
            scheduler = SchedulerJob(executor=self.null_exec, subdir=dag.fileloc, num_runs=1)
            scheduler.run()
            
            assert len(session.query(TaskInstance).filter(TaskInstance.dag_id == dag_id).all()) == 0
            session.commit()
            assert [] == self.null_exec.sorted_tasks
            
            
            
            
            bf_exec = MockExecutor()
            backfill = BackfillJob(executor=bf_exec, dag=dag, start_date=DEFAULT_DATE, end_date=DEFAULT_DATE)
            backfill.run()
            
            assert len(session.query(TaskInstance).filter(TaskInstance.dag_id == dag_id).all()) == 1
            assert [
                (TaskInstanceKey(dag.dag_id, 'dummy', DEFAULT_DATE, 1), (State.SUCCESS, None)),
            ] == bf_exec.sorted_tasks
            session.commit()
            scheduler = SchedulerJob(dag.fileloc, executor=self.null_exec, num_runs=1)
            scheduler.run()
            
            assert len(session.query(TaskInstance).filter(TaskInstance.dag_id == dag_id).all()) == 1
            session.commit()
            assert [] == self.null_exec.sorted_tasks
    @pytest.mark.quarantined
    def test_scheduler_task_start_date(self):