new(tests): Explicit test for EXTDELEGATECALL value cost

[pdobacz]

🗒️ Description

There has been divergence in EXTDELEGATECALL implementations, whereby effectively non-zero value call (non-zero value coming from an outer EXTCALL!) was charging an additional 9000. C.f. EIP update for background: ethereum/EIPs#8990, in this PR we give extra emphasis that the additional cost, and other value-related rules, are only relevant to EXTCALL.

Unfortunately, due to the 63/64th rule on calls, I had to complicate gas_test.py an additional bit :/.

EDIT: Note that all 3 EXT*CALL can, and are tested the same way, for completeness (see comment below)

🔗 Related Issues

NA, reported on discord. We did have a test which covered this, but without an explicit post state assertion.

✅ 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]

Small comment, thanks!