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/models/test_taskinstance.py
dag.create_dagrun(
                run_type=DagRunType.SCHEDULED,
                state=state,
                execution_date=execution_date,
                start_date=pendulum.now('UTC'),
                session=session,
            )
            ti = TI(task=task, execution_date=execution_date)
            ti.set_state(state=State.SUCCESS, session=session)
            return ti
        with create_session() as session:  
            date = cast(pendulum.DateTime, pendulum.parse('2019-01-01T00:00:00+00:00'))
            ret = []
            for idx, state in enumerate(scenario):
                new_date = date.add(days=idx)
                ti = get_test_ti(session, new_date, state)
                ret.append(ti)
            return ret
    _prev_dates_param_list = (
        param('cron/catchup', '0 0 * * * ', True),
        param('cron/no-catchup', '0 0 * * *', False),
        param('no-sched/catchup', None, True),
        param('no-sched/no-catchup', None, False),
        param('timedelta/catchup', datetime.timedelta(days=1), True),
        param('timedelta/no-catchup', datetime.timedelta(days=1), False),
    )
    @parameterized.expand(_prev_dates_param_list)
    def test_previous_ti(self, _, schedule_interval, catchup) -> None: