### 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
try:
                ti.run(ignore_ti_state=ignore_ti_state)
            except AirflowException:
                pass
        assert ti.try_number == 1
        
        
        
        
        
        run_with_error(ti, ignore_ti_state=True)
        assert ti.state == State.UP_FOR_RETRY
        assert ti.try_number == 2
        with create_session() as session:
            ti.refresh_from_db(lock_for_update=True, session=session)
            ti.state = State.SCHEDULED
            session.merge(ti)
        
        executor.do_update = True
        do_schedule()
        ti.refresh_from_db()
        assert ti.state == State.SUCCESS
    @pytest.mark.skip(reason="This test needs fixing. It's very wrong now and always fails")
    def test_retry_handling_job(self):