Add internal function (only used for testing at the moment)
`_bpy._driver_secure_code_test`.
Add test `script_pyapi_bpy_driver_secure_eval` to serves two purposes:
- Ensure expressions that should be insecure remain so when upgrading
Python or making any changes in this area.
- Ensure new versions of Python don't introduce new byte-codes that
prevent existing expressions from being executed
(happened when upgrading from 3.7, see [0]).
[0]: dfa5201763
