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.".

airflow/utils/file.py
"""
    Heuristic that guesses whether a Python file contains an Airflow DAG definition.
    :param file_path: Path to the file to be checked.
    :param safe_mode: Is safe mode active?. If no, this function always returns True.
    :param zip_file: if passed, checks the archive. Otherwise, check local filesystem.
    :return: True, if file might contain DAGS.
    """
    if not safe_mode:
        return True
    if zip_file:
        with zip_file.open(file_path) as current_file:
            content = current_file.read()
    else:
        if zipfile.is_zipfile(file_path):
            return True
        with open(file_path, 'rb') as dag_file:
            content = dag_file.read()
    content = content.lower()
    return all(s in content for s in (b'dag', b'airflow'))