Add `run-turbopack-compiler` trace span (#81917)
Add a span to `.next/trace` for Turbopack just as there is for Webpack
This span is consistently ~400ms longer than the `Compiled successfully in X ms` message though, due to the worker startup. With the worker disabled, it's accurate within 10ms.
<img width="2560" height="349" alt="Bildschirmfoto 2025-07-22 um 11 27 52" src="https://github.com/user-attachments/assets/4c12198c-02dd-4075-97a9-13342976ac41" />
