BUGFIX: Make `Andersen` work with both the legacy and the modern NumPy PRNGs

Closes #1533 (closed)

A test is also added to test both legacy and modern NumPy PRNGs.

The bugfix may be relatively straightforward, so I would like to merge it after a few days unless any concerns are raised.

Checklist

• I am familiar with ASE's contribution guidelines.
• Doc strings in code changed in this MR are up to date.
• Unit tests have been added for new or changed code.
• Issue is resolved via "closes #XXXX" if applicable.