Don't compile a regex in a loop in trie_diff

[0xaatif]

zk_evm/zero/src/bin/trie_diff.rs

Line 133 in 177ae27

let re = Regex::new(r"block:(\d+) batch:(\d+)")?;

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