### 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
assert orm_dag is not None
        self.scheduler_job = SchedulerJob(subdir=os.devnull)
        self.scheduler_job.processor_agent = mock.MagicMock()
        dag = self.scheduler_job.dagbag.get_dag('test_verify_integrity_if_dag_not_changed', session=session)
        self.scheduler_job._create_dag_runs([orm_dag], session)
        drs = DagRun.find(dag_id=dag.dag_id, session=session)
        assert len(drs) == 1
        dr = drs[0]
        
        with mock.patch('airflow.jobs.scheduler_job.DagRun.verify_integrity') as mock_verify_integrity:
            self.scheduler_job._schedule_dag_run(dr, session)
            mock_verify_integrity.assert_not_called()
        session.flush()
        tis_count = (
            session.query(func.count(TaskInstance.task_id))
            .filter(
                TaskInstance.dag_id == dr.dag_id,
                TaskInstance.execution_date == dr.execution_date,
                TaskInstance.task_id == dr.dag.tasks[0].task_id,
                TaskInstance.state == State.SCHEDULED,
            )
            .scalar()
        )
        assert tis_count == 1
        latest_dag_version = SerializedDagModel.get_latest_version_hash(dr.dag_id, session=session)
        assert dr.dag_hash == latest_dag_version
        session.rollback()
        session.close()
    @pytest.mark.quarantined
    def test_verify_integrity_if_dag_changed(self, dag_maker):