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/jobs/test_scheduler_job.py
"""
    These tests are designed to detect changes in the number of queries for
    different DAG files. These tests allow easy detection when a change is
    made that affects the performance of the SchedulerJob.
    """
    def setUp(self) -> None:
        clear_db_runs()
        clear_db_pools()
        clear_db_dags()
        clear_db_sla_miss()
        clear_db_import_errors()
        clear_db_serialized_dags()
        clear_db_dags()
    @parameterized.expand(
        [
            
            
            (23, 1, 1),  
            
            (23, 1, 5),  
            
            (95, 10, 10),  
        ]
    )
    @pytest.mark.quarantined
    def test_execute_queries_count_with_harvested_dags(self, expected_query_count, dag_count, task_count):