perf(turbopack): Drop `tokio::fs` usages (#80674)
### What?
`std::fs` with manual `spawn_blocking` is better than using `tokio::fs`
### Why?
`tokio::fs` inevitably calls `spawn_blocking` internally, but it calls `spawn_blocking` way too much time
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Co-authored-by: graphite-app[bot] <96075541+graphite-app[bot]@users.noreply.github.com>
Co-authored-by: Tobias Koppers <tobias.koppers@googlemail.com>
