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
self._clean()
    def tearDown(self) -> None:
        self._clean()
    @parameterized.expand(
        [
            
            (10, False),
            (5, True),
        ]
    )
    def test_execute_queries_count(self, expected_query_count, mark_success):
        with create_session() as session:
            dag = DAG('test_queries', start_date=DEFAULT_DATE)
            task = DummyOperator(task_id='op', dag=dag)
            ti = TI(task=task, execution_date=datetime.datetime.now())
            ti.state = State.RUNNING
            session.merge(ti)
            dag.create_dagrun(
                execution_date=ti.execution_date,
                state=State.RUNNING,
                run_type=DagRunType.SCHEDULED,
                session=session,
            )
        with assert_queries_count(expected_query_count):
            ti._run_raw_task(mark_success=mark_success)
    def test_execute_queries_count_store_serialized(self):