refactor(tests): encode z, y as big-endian in test_point_eval_gas

[Thegaram]

🗒️ Description

This is just a nitpick fix to the tests.

The EIP-4844 point-evaluation precompile z and y inputs are supposed to be encoded big-endian, but test_point_evaluation_precompile_gas uses little-endian. For this gas test, this doesn't make a difference, but I found it confusing.

Changed it to use Z_Y_VALID_ENDIANNESS instead, consistent with test_point_evaluation_precompile.py.

🔗 Related Issues or PRs

N/A.

✅ Checklist

• All: Ran fast static checks to avoid unnecessary CI fails, see also Code Standards and Enabling Pre-commit Checks:

  just static

• All: PR title adheres to the repo standard - it will be used as the squash commit message and should start type(scope):.
• All: Considered updating the online docs in the ./docs/ directory.
• All: Set appropriate labels for the changes (only maintainers can apply labels).
• Tests: Ran mkdocs serve locally and verified the auto-generated docs for new tests in the Test Case Reference are correctly formatted.
• Tests: For PRs implementing a missed test case, update the post-mortem document to add an entry the list.
• Ported Tests: All converted JSON/YML tests from ethereum/tests or tests/static have been assigned @ported_from marker.

Cute Animal Picture