Think about upcoming built-in snapshot testing

[hildjj]

See: https://nodejs.org/api/test.html#snapshot-testing

Added in v22.3.0, node will eventually have snapshot testing built-in. There are a couple of things this library could do:

• Track changes to these experimental interfaces
• Provide a polyfill for earlier versions of node to ease the transition
• Generate the exact same format as node (plain JSON at the moment), so snapshots pass in the future
• Provide an additional snapshot formatter that uses serialize-json or cbor2