perf: fs performance improvements (#1007)

* perf: use pojo for fs link-hop cache

* perf: reduce fs operations in sync hop lookup

* perf: do not run guards outside roots, reduce path.* calls in isEscape helper

* perf: cache not-found fs hop results

* refactor: align async nextHop with sync

* perf: cache async readHopLink

* Don't rely on try/catch; we've measured it as a performance issue on older versions of node

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Co-authored-by: Greg Magolan <gmagolan@gmail.com>