chore(filler): always delete output directory with no tests (without specifying --no-html)

[danceratopz]

🗒️ Description

Some suggestions no how we can solve ethereum/execution-specs#1548 without having to add --no-html.

This:

• Uses a hook wrapper to make sure that we delete the directory after the pytest-html plugin has written its html output.
• Filters out the pytest-html "Generated html report:" line from the summary to avoid confusion.

The whole thing is hacky, but it's a better solution imo. This

• The logic in pytest_terminal_summary is worse/more complex.
• The logic in ptyest_sessionfinish is slightly better.

If we want to be less hacky, then the other option is to stop generating html by default.

🔗 Related Issues

✅ Checklist

• All: Set appropriate labels for the changes.
• All: Considered squashing commits to improve commit history.
• All: Added an entry to CHANGELOG.md.
• All: Considered updating the online docs in the ./docs/ directory.
• Tests: All converted JSON/YML tests from ethereum/tests have been added to converted-ethereum-tests.txt.
• Tests: A PR with removal of converted JSON/YML tests from ethereum/tests have been opened.
• Tests: Included the type and version of evm t8n tool used to locally execute test cases: e.g., ref with commit hash or geth 1.13.1-stable-3f40e65.
• Tests: Ran mkdocs serve locally and verified the auto-generated docs for new tests in the Test Case Reference are correctly formatted.