Turbopack: next/dynamic use transitions instead of AST analysis (#73627)
- Before, there was a separate AST traversal that collected `next-dynamic` imports
- Now, we use transitions (which are inserted by the existing next-custom-transform) to tell Turbopack about the next-dynamic imports
- Unlike Webpack (where the react-loadable identifiers are `path/to/parent-module -> ./imported-client`), Turbopack just uses the module id: `[project]/path/to/imported-client.js [app-client] (ecmascript, next/dynamic entry)`
- the `next-dynamic` transition only inserts the marker module (i.e. for the SSR `import()`)
- the `next-dynamic-client` transition inserts the marker module and changes the module context (used to get the client module name)
- Now, we use the correct `AvailabilityInfo` for the next/dynamic chunks to preload, and they are not explicitly emitted. If they are for some reason not the same chunks that are actually emitted for the dynamic import, you get a hard error. (Previously, they didn't use the same `AvailabilityInfo` as the real async chunks, so they usually bundled another copy of React, and also had a different chunk name hash)
- For Turbopack, react-loadable manifests are now scoped per page instead of globally