### Body

The `test_no_orphan_process_will_be_left` in `TestSchedulerJob` is really flaky.

Before we know how to fix it, I will quarantine it:

https://github.com/apache/airflow/pull/18691/checks?check_run_id=3811660138

```
  =================================== FAILURES ===================================
  _____________ TestSchedulerJob.test_no_orphan_process_will_be_left _____________
  
  self = <tests.jobs.test_scheduler_job.TestSchedulerJob object at 0x7fc2f91d2ac8>
  
      def test_no_orphan_process_will_be_left(self):
          empty_dir = mkdtemp()
          current_process = psutil.Process()
          old_children = current_process.children(recursive=True)
          self.scheduler_job = SchedulerJob(
              subdir=empty_dir, num_runs=1, executor=MockExecutor(do_update=False)
          )
          self.scheduler_job.run()
          shutil.rmtree(empty_dir)
      
          # Remove potential noise created by previous tests.
          current_children = set(current_process.children(recursive=True)) - set(old_children)
  >       assert not current_children
  E       AssertionError: assert not {psutil.Process(pid=2895, name='pytest', status='running', started='06:53:45')}
  
```

### Committer

- [X] I acknowledge that I am a maintainer/committer of the Apache Airflow project.
tests/test_utils/asserts.py
#
#
import logging
import re
import traceback
from collections import Counter
from contextlib import contextmanager
from sqlalchemy import event
import airflow.settings
log = logging.getLogger(__name__)
def assert_equal_ignore_multiple_spaces(case, first, second, msg=None):
    def _trim(s):
        return re.sub(r"\s+", " ", s.strip())
    return case.assertEqual(_trim(first), _trim(second), msg)
class CountQueries:
    """
    Counts the number of queries sent to Airflow Database in a given context.
    Does not support multiple processes. When a new process is started in context, its queries will
    not be included.
    """
    def __init__(self):
        self.result = Counter()
    def __enter__(self):
        event.listen(airflow.settings.engine, "after_cursor_execute", self.after_cursor_execute)
        return self.result
    def __exit__(self, type_, value, tb):