pyoxy: `AttributeError: module 'importlib' has no attribute 'util'`

Works fine in a normal Python:

```bash
$ python3
Python 3.10.12 (main, Nov 20 2023, 15:14:05) [GCC 11.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import importlib
>>> importlib.util

```

raise `AttributeError` in `pyoxy`:

```bash
$ ./pyoxy run-python
Python 3.10.9 (main, Dec 21 2022, 04:02:04) [Clang 14.0.3 ] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import importlib
>>> importlib.util
Traceback (most recent call last):
File "", line 1, in
AttributeError: module 'importlib' has no attribute 'util'
```

Reproduce the failure by running `./pyoxy run-python` and evaluating `importlib.util` in the embedded Python prompt, then compare it with the normal Python behavior shown in the report. Trace the `pyoxy` entry point and packaging setup to identify why the attribute is unavailable; done means `importlib.util` works in `pyoxy` as it does in normal Python.

Written by the indexing model from the issue text.