**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
try:
            dags_folder = mkdtemp()
            filename_to_parse = os.path.join(dags_folder, TEMP_DAG_FILENAME)
            
            with open(filename_to_parse, 'w') as file_to_parse:
                file_to_parse.writelines(UNPARSEABLE_DAG_FILE_CONTENTS)
            self.run_single_scheduler_loop_with_no_dags(dags_folder)
        finally:
            shutil.rmtree(dags_folder)
        
        self.run_single_scheduler_loop_with_no_dags(dags_folder)
        with create_session() as session:
            import_errors = session.query(errors.ImportError).all()
        assert len(import_errors) == 0
    def test_import_error_tracebacks(self):