perf(turbopack): Remove `ImportBinding` fragments (#78470)
### What?
Make the `ImportBinding` node a phantom node.
### Why?
Because they are not used. We have to import directly from the original
module because of the static analysis like `next/dynamic`. So I modified
the tree shaking to import directly with
https://github.com/vercel/next.js/pull/71704. But #71704 didn't remove
the concept of `ImportBinding`. This PR finishes the work of using
direct imports.
Additionally, this PR introduces `ReexportBinding` fragments because
these are not phantom nodes. I'll check if it would be possible to
remove `ReexportBinding` fragments with follow-up PRs.
### How?
- Closes PACK-4366
