feat(test-client-clis): add stream-mode opcode count support for geth

[spencer-tb]

🗒️ Description

Extends _evaluate_stream() in TransitionTool to read opcode count output from opcodes.json (mirrors existing _evaluate_filesystem() logic), updates safe_t8n_args() to set --output.basedir and --opcode.count flags when supports_opcode_count is true (even without --trace), and enables supports_opcode_count = True for GethTransitionTool.

The EELS benchmark framework uses opcode frequency counts to verify that benchmark tests exercise the intended opcodes at the expected iteration counts. This is critical for the gas repricing work where we need precise control over how many times each opcode executes.

Currently, benchmark tests can only be filled with opcode count verification using evmone or EELS. However, for Amsterdam (which evmone does not support currently) we need to fill benchmark tests with geth. As geth has this implemented the hope is to use geth as the default benchmark test filler moving forward. EELS is too slow.

Previously, opcode count support in EELS was only wired for filesystem-mode tools (evmone). Since geth uses stream mode (t8n_use_stream = True), the _evaluate_stream() path needed the same opcode count file reading that _evaluate_filesystem() already had. This PR adds that wiring so geth has full feature parity with evmone for benchmark fills.

🔗 Related Issues or PRs

• Original EELS request: ethereum/execution-specs#1554 — feature request for opcode count support across t8n tools
• evmone implementation: ipsilon/evmone#1256 (issue) → ipsilon/evmone#1274 (merged PR)
• EELS integration: ethereum/execution-spec-tests#1956 — Mario's PR adding EELS-side --opcode.count support
• Geth --opcode.count PR: ethereum/go-ethereum#33800 — companion PR adding --opcode.count flag to geth's evm t8n

✅ Checklist

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

  uvx tox -e 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).

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.07%. Comparing base (87a414f) to head (548e36c).
⚠️ Report is 2 commits behind head on forks/amsterdam.

Additional details and impacted files

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  Coverage            86.07%   86.07%           
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  Files                  599      599           
  Lines                39472    39472           
  Branches              3780     3780           
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  Hits                 33977    33977           
  Misses                4862     4862           
  Partials               633      633           

Flag	Coverage Δ
unittests	86.07% <ø> (ø)

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[marioevz]

Nice addition, just one comment, and we should wait until the Geth's PR is reviewed and eventually merged.

[spencer-tb]

Changes implemented and tested with fill again. Lets wait for the Geth PR. Thanks.