Add experimental support for loading snapshots in the embedder API
by adding a public opaque wrapper for our `SnapshotData` struct and
allowing embedders to pass it to the relevant setup functions.
Where applicable, use these helpers to deduplicate existing code
in Node.js’s startup path.
This has shown a 40 % startup performance increase for a real-world
application, even with the somewhat limited current support for
built-in modules.
The documentation includes a note about no guarantees for API or
ABI stability for this feature while it is experimental.
PR-URL: https://github.com/nodejs/node/pull/45888
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Anna Henningsen