chore: switch from tap to node:test and Borp

This was a pretty mechanical change. To do this, I:

* Uninstalled `tap` and replaced it with `borp`
* Manually rewrote tests to use `node:assert` and `t.after` for cleanup

See [multi-core-indexer#39] for a similar patch on another repo.

[multi-core-indexer#39]: digidem/multi-core-indexer#39