**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,
)
```
airflow/jobs/scheduler_job.py
self.log.error("Couldn't find dag %s in DagBag/DB!", dag_run.dag_id)
            return 0
        if (
            dag_run.start_date
            and dag.dagrun_timeout
            and dag_run.start_date < timezone.utcnow() - dag.dagrun_timeout
        ):
            dag_run.state = State.FAILED
            dag_run.end_date = timezone.utcnow()
            self.log.info("Run %s of %s has timed-out", dag_run.run_id, dag_run.dag_id)
            session.flush()
            
            self._update_dag_next_dagruns([session.query(DagModel).get(dag_run.dag_id)], session)
            callback_to_execute = DagCallbackRequest(
                full_filepath=dag.fileloc,
                dag_id=dag.dag_id,
                execution_date=dag_run.execution_date,
                is_failure_callback=True,
                msg='timed_out',
            )
            
            self._send_dag_callbacks_to_processor(dag_run, callback_to_execute)
            return 0
        if dag_run.execution_date > timezone.utcnow() and not dag.allow_future_exec_dates:
            self.log.error("Execution date is in future: %s", dag_run.execution_date)
            return 0
        if dag.max_active_runs:
            if (
                len(currently_active_runs) >= dag.max_active_runs
                and dag_run.execution_date not in currently_active_runs