* Add a benchmark for snapshot::account::to_fat_rlps()
`to_fat_rlps()` is a hot call during snapshots. I don't think it has a perf problem per se, but better to have benchmark for it.
The data used is a piece of Ropsten data sized to the ~95% percentile of account size on that network.
* Benchmark with more chunks, including mainnet data
* whitespace
* Move `used_code` inside the benchmark iteration
* Revert "Move `used_code` inside the benchmark iteration"
This reverts commit cff33ab30acbd1c009e745f646f1cc655ee01d8c.
