Turbopack: Remove undocumented legacy syntax for built-in conditions (e.g. foreign, browser) (#83068)
- https://github.com/vercel/next.js/pull/82857 provides a better way to do this that we intend to document.
- This syntax was never documented (outside of the types and tests). You wouldn't be able to figure out the built-in conditions without digging through the Turbopack source code.