### Body

The `test_no_orphan_process_will_be_left` in `TestSchedulerJob` is really flaky.

Before we know how to fix it, I will quarantine it:

https://github.com/apache/airflow/pull/18691/checks?check_run_id=3811660138

```
  =================================== FAILURES ===================================
  _____________ TestSchedulerJob.test_no_orphan_process_will_be_left _____________
  
  self = <tests.jobs.test_scheduler_job.TestSchedulerJob object at 0x7fc2f91d2ac8>
  
      def test_no_orphan_process_will_be_left(self):
          empty_dir = mkdtemp()
          current_process = psutil.Process()
          old_children = current_process.children(recursive=True)
          self.scheduler_job = SchedulerJob(
              subdir=empty_dir, num_runs=1, executor=MockExecutor(do_update=False)
          )
          self.scheduler_job.run()
          shutil.rmtree(empty_dir)
      
          # Remove potential noise created by previous tests.
          current_children = set(current_process.children(recursive=True)) - set(old_children)
  >       assert not current_children
  E       AssertionError: assert not {psutil.Process(pid=2895, name='pytest', status='running', started='06:53:45')}
  
```

### Committer

- [X] I acknowledge that I am a maintainer/committer of the Apache Airflow project.
tests/jobs/test_scheduler_job.py
session = settings.Session()
        with dag_maker('test_execute_helper_reset_orphaned_tasks') as dag:
            op1 = DummyOperator(task_id='op1')
        dr = dag_maker.create_dagrun()
        dr2 = dag.create_dagrun(
            run_type=DagRunType.BACKFILL_JOB,
            state=State.RUNNING,
            execution_date=DEFAULT_DATE + datetime.timedelta(1),
            start_date=DEFAULT_DATE,
            session=session,
        )
        ti = dr.get_task_instance(task_id=op1.task_id, session=session)
        ti.state = State.QUEUED
        ti2 = dr2.get_task_instance(task_id=op1.task_id, session=session)
        ti2.state = State.QUEUED
        session.commit()
        processor = mock.MagicMock()
        self.scheduler_job = SchedulerJob(num_runs=0)
        self.scheduler_job.processor_agent = processor
        self.scheduler_job.adopt_or_reset_orphaned_tasks()
        ti = dr.get_task_instance(task_id=op1.task_id, session=session)
        assert ti.state == State.NONE
        ti2 = dr2.get_task_instance(task_id=op1.task_id, session=session)
        assert ti2.state == State.QUEUED, "Tasks run by Backfill Jobs should not be reset"
    @mock.patch('airflow.jobs.scheduler_job.DagFileProcessorAgent')
    def test_executor_end_called(self, mock_processor_agent):