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
with DAG('test_get_rendered_k8s_spec', start_date=DEFAULT_DATE):
            task = BashOperator(task_id='op1', bash_command="{{ task.task_id }}")
        ti = TI(task=task, execution_date=DEFAULT_DATE)
        expected_pod_spec = {
            'metadata': {
                'annotations': {
                    'dag_id': 'test_get_rendered_k8s_spec',
                    'execution_date': '2016-01-01T00:00:00+00:00',
                    'task_id': 'op1',
                    'try_number': '1',
                },
                'labels': {
                    'airflow-worker': 'worker-config',
                    'airflow_version': version,
                    'dag_id': 'test_get_rendered_k8s_spec',
                    'execution_date': '2016-01-01T00_00_00_plus_00_00',
                    'kubernetes_executor': 'True',
                    'task_id': 'op1',
                    'try_number': '1',
                },
                'name': mock.ANY,
                'namespace': 'default',
            },
            'spec': {
                'containers': [