Don't compile a regex in a loop in `trie_diff`

[0xaatif]

https://github.com/0xPolygonZero/zk_evm/blob/177ae2702165e27a531fbcb4d692ac83b548173c/zero/src/bin/trie_diff.rs#L133

https://docs.rs/lazy-regex/latest/lazy_regex/macro.regex_captures.html

Let's also get rid of the indexing and use a nice library for this

[0xaatif]

cc @atanmarko