It seems that the `test_find_not_should_ignore_path` test has some dependency on side-effects from other tests. 

For example it failed here:

https://github.com/apache/airflow/pull/10983/checks?check_run_id=1127304894#step:6:1043

```
>       self.assertEqual(detected_files, should_not_ignore_files)
E       AssertionError: Items in the second set but not the first:
E       'test_load.py'
E       'test_load_sub1.py'
```

And re-running it in a clean system works just fine in the same combination of python/db.

**What you expected to happen**:

The test should clean up /restore everything it needs before running or a test that makes side-effects is found and fixed. 

For now I am moving the test to "heisentests with appropriate note.".

tests/plugins/test_plugin_ignore.py
"""
        Test that the .airflowignore work and whether the file is properly ignored.
        """
        detected_files = set()
        should_ignore_files = {
            'test_notload.py',
            'test_notload_sub.py',
            'test_noneload_sub1.py',
            'test_shouldignore.py',
        }
        should_not_ignore_files = {
            'test_load.py',
            'test_load_sub1.py',
        }
        ignore_list_file = ".airflowignore"
        for file_path in find_path_from_directory(self.plugin_folder_path, ignore_list_file):
            if not os.path.isfile(file_path):
                continue
            _, file_ext = os.path.splitext(os.path.split(file_path)[-1])
            if file_ext != '.py':
                continue
            detected_files.add(os.path.basename(file_path))
        self.assertEqual(detected_files, should_not_ignore_files)
        self.assertEqual(detected_files & should_ignore_files, set())