Update tiny model creation script
# What does this PR do?

- Update `UNCONVERTIBLE_MODEL_ARCHITECTURES` with a few recent models: they don't have processor class (or not included in the `XXX_MAPPING_NAMES`)
- Make the detection of model test class more robust.
_The documentation is not available anymore as the PR was closed or merged._<|||||>The docs for this PR live [here](https://moon-ci-docs.huggingface.co/docs/transformers/pr_22202). All of your documentation changes will be reflected on that endpoint.