**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
"""
        Process the given file.
        :param result_channel: the connection to use for passing back the result
        :type result_channel: multiprocessing.Connection
        :param parent_channel: the parent end of the channel to close in the child
        :type parent_channel: multiprocessing.Connection
        :param file_path: the file to process
        :type file_path: str
        :param pickle_dags: whether to pickle the DAGs found in the file and
            save them to the DB
        :type pickle_dags: bool
        :param dag_ids: if specified, only examine DAG ID's that are
            in this list
        :type dag_ids: list[str]
        :param thread_name: the name to use for the process that is launched
        :type thread_name: str
        :param callback_requests: failure callback to execute
        :type callback_requests: List[airflow.utils.callback_requests.CallbackRequest]
        :return: the process that was launched
        :rtype: multiprocessing.Process
        """
        
        log: logging.Logger = logging.getLogger("airflow.processor")
        
        
        log.info("Closing parent pipe")
        parent_channel.close()
        del parent_channel
        set_context(log, file_path)
        setproctitle(f"airflow scheduler - DagFileProcessor {file_path}")