fix(fw): max stack height calculation in __add__

[pdobacz]

🗒️ Description

Split out of #785 with a unit test added.

I've noticed that the algorithm might not handle all cases well, and I am proposing an alternative. I've left all my overly verbose comments in the code to illustrate the train of thought, as this has been quite hard to grasp the original code intentions (maybe there has been an easier fix hidden from my sight there).

🔗 Related Issues

n/a

✅ 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.

[marioevz]

This is great, thanks so much for implementing this. I think the concept I was missing is the stack-bottom, it makes it easier to follow this implementation.

I verified the resulting fixtures and they are exactly the same, so it's safe to merge.