**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
super().__init__()
        self.dag_ids = dag_ids
        self._log = log
    @provide_session
    def manage_slas(self, dag: DAG, session: Session = None) -> None:
        """
        Finding all tasks that have SLAs defined, and sending alert emails
        where needed. New SLA misses are also recorded in the database.
        We are assuming that the scheduler runs often, so we only check for
        tasks that should have succeeded in the past hour.
        """
        self.log.info("Running SLA Checks for %s", dag.dag_id)
        if not any(isinstance(ti.sla, timedelta) for ti in dag.tasks):
            self.log.info("Skipping SLA check for %s because no tasks in DAG have SLAs", dag)
            return
        qry = (
            session.query(TI.task_id, func.max(TI.execution_date).label('max_ti'))
            .with_hint(TI, 'USE INDEX (PRIMARY)', dialect_name='mysql')
            .filter(TI.dag_id == dag.dag_id)
            .filter(or_(TI.state == State.SUCCESS, TI.state == State.SKIPPED))
            .filter(TI.task_id.in_(dag.task_ids))
            .group_by(TI.task_id)
            .subquery('sq')
        )
        max_tis: List[TI] = (
            session.query(TI)
            .filter(
                TI.dag_id == dag.dag_id,
                TI.task_id == qry.c.task_id,
                TI.execution_date == qry.c.max_ti,