Implement standardized JSON format for slow block logging to enable
cross-client performance analysis and protocol research.
This change is part of the Cross-Client Execution Metrics initiative
proposed by Gary Rong: https://hackmd.io/dg7rizTyTXuCf2LSa2LsyQ
The standardized metrics enabled data-driven analysis like the EIP-7907
research: https://ethresear.ch/t/data-driven-analysis-on-eip-7907/23850
JSON format includes:
- block: number, hash, gas_used, tx_count
- timing: execution_ms, total_ms
- throughput: mgas_per_sec
- state_reads: accounts, storage_slots, bytecodes, code_bytes
- state_writes: accounts, storage_slots, bytecodes
- cache: account/storage/code hits, misses, hit_rate
This should come after merging #33522
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Co-authored-by: Gary Rong <garyrong0905@gmail.com>