feat(tests): EIP-7928 cover many storage changes for one account

[pirapira]

🗒️ Description

Add test_bal_many_storage_writes_single_account to the EIP-7928 block-access-list suite, parametrized over 17, 32, and 128 distinct storage slots written by a single transaction to one contract.

Existing BAL storage tests touch at most a handful of slots per account — test_bal_cross_tx_storage_chain writes eight, one slot per transaction. This adds coverage for a much higher per-account, per-transaction storage-change cardinality: the block access list must record every slot, in ascending order, at a single block access index. It stresses any client that records or preloads an account's BAL storage keys into a fixed-size buffer.

This scenario was not covered by the existing suite and surfaced a fixed-size-buffer overflow in a stateless client implementation, so a post-mortem entry is also added in docs/writing_tests/post_mortems.md.

Filled clean for Amsterdam (blockchain + engine fixture formats); the produced BAL contains 17 / 32 / 128 storage changes for the recipient as expected.

🔗 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.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.53%. Comparing base (9d7738b) to head (114755b).

Additional details and impacted files

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  Hits                 29782    29782           
  Misses                2595     2595           
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Flag	Coverage Δ
unittests	90.53% <ø> (ø)

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[spencer-tb]

Thanks for the tests! LGTM