Turbopack: Add a stress test / fuzzer that tries creating many symlinks in a tight loop (#88667)
In an attempt to reproduce https://github.com/vercel/next.js/discussions/88382, this tries creating and updating a bunch of symlinks/junction points in a tight loop with some parallelism. However, I've been unable to reproduce the error reported in that discussion.
I don't care about the code quality here, so this was LLM-generated with very lightweight review.
A simplified version of the fuzzer is also included as a unit test in `turbo-tasks-fs`. This version only does a few iterations and runs very quickly.