**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
with mock.patch.dict(
            "os.environ",
            {
                "PERF_DAGS_COUNT": str(dag_count),
                "PERF_TASKS_COUNT": str(task_count),
                "PERF_START_AGO": "1d",
                "PERF_SCHEDULE_INTERVAL": "30m",
                "PERF_SHAPE": "no_structure",
            },
        ), conf_vars(
            {
                ('scheduler', 'use_job_schedule'): 'True',
                ('core', 'load_examples'): 'False',
                ('core', 'store_serialized_dags'): 'True',
            }
        ), mock.patch.object(
            settings, 'STORE_SERIALIZED_DAGS', True
        ):
            dagruns = []