This tests fails occasionally on mysql at least:

https://github.com/apache/airflow/pull/11555/checks?check_run_id=1260840314#step:9:1125

```
=================================== FAILURES ===================================
_____________ TestSchedulerJob.test_no_orphan_process_will_be_left _____________

self = <tests.jobs.test_scheduler_job.TestSchedulerJob testMethod=test_no_orphan_process_will_be_left>

    def test_no_orphan_process_will_be_left(self):
        empty_dir = mkdtemp()
        current_process = psutil.Process()
        old_children = current_process.children(recursive=True)
        scheduler = SchedulerJob(subdir=empty_dir,
                                 num_runs=1,
                                 executor=MockExecutor(do_update=False))
        scheduler.run()
        shutil.rmtree(empty_dir)
    
        # Remove potential noise created by previous tests.
        current_children = set(current_process.children(recursive=True)) - set(
            old_children)
>       self.assertFalse(current_children)
E       AssertionError: {psutil.Process(pid=3474, name='/usr/local/bin/', status='running', started='19:26:22')} is not false

tests/jobs/test_scheduler_job.py:871: AssertionError
```



tests/jobs/test_scheduler_job.py
"""
        DagRuns with one unfinished and one failed root task -> RUNNING
        """
        
        
        dag_id = 'test_dagrun_states_root_fail_unfinished'
        dag = self.dagbag.get_dag(dag_id)
        dr = dag.create_dagrun(
            run_type=DagRunType.SCHEDULED,
            execution_date=DEFAULT_DATE,
            state=State.RUNNING,
        )
        self.null_exec.mock_task_fail(dag_id, 'test_dagrun_fail', DEFAULT_DATE)
        with pytest.raises(AirflowException):
            dag.run(start_date=dr.execution_date, end_date=dr.execution_date, executor=self.null_exec)
        
        
        with create_session() as session:
            ti = dr.get_task_instance('test_dagrun_unfinished', session=session)
            ti.state = State.NONE
            session.commit()
        dr.update_state()
        assert dr.state == State.RUNNING
    def test_dagrun_root_after_dagrun_unfinished(self):