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 = models.DAG(dag_id='test_not_requeue_non_requeueable_task_instance')
        
        
        task = BaseSensorOperator(
            task_id='test_not_requeue_non_requeueable_task_instance_op',
            dag=dag,
            pool='test_pool',
            owner='airflow',
            start_date=timezone.datetime(2016, 2, 1, 0, 0, 0),
        )
        ti = TI(task=task, execution_date=timezone.utcnow(), state=State.QUEUED)
        with create_session() as session:
            session.add(ti)
            session.commit()
        all_deps = RUNNING_DEPS | task.deps
        all_non_requeueable_deps = all_deps - REQUEUEABLE_DEPS
        patch_dict = {}
        for dep in all_non_requeueable_deps:
            class_name = dep.__class__.__name__
            dep_patch = patch(f'{dep.__module__}.{class_name}.{dep._get_dep_statuses.__name__}')
            method_patch = dep_patch.start()
            method_patch.return_value = iter([TIDepStatus('mock_' + class_name, True, 'mock')])
            patch_dict[class_name] = (dep_patch, method_patch)
        for class_name, (dep_patch, method_patch) in patch_dict.items():
            method_patch.return_value = iter([TIDepStatus('mock_' + class_name, False, 'mock')])
            ti.run()
            assert ti.state == State.QUEUED
            dep_patch.return_value = TIDepStatus('mock_' + class_name, True, 'mock')