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
task = DummyOperator(
        task_id="dummy",
        queue="test_queue",
        pool="test_pool1",
        pool_slots=3,
        priority_weight=10,
        run_as_user="test",
        retries=30,
        executor_config={"KubernetesExecutor": {"image": "myCustomDockerImage"}},
    )
    ti = TI(task, execution_date=pendulum.datetime(2020, 1, 1))
    ti.refresh_from_task(task, pool_override=pool_override)
    assert ti.queue == task.queue
    if pool_override:
        assert ti.pool == pool_override
    else:
        assert ti.pool == task.pool
    assert ti.pool_slots == task.pool_slots
    assert ti.priority_weight == task.priority_weight_total
    assert ti.run_as_user == task.run_as_user
    assert ti.max_tries == task.retries
    assert ti.executor_config == task.executor_config
    assert ti.operator == DummyOperator.__name__
class TestRunRawTaskQueriesCount(unittest.TestCase):