[racket-dev] dependencies for `racket-test` package

Currently, the `racket-test` package has very few declared
dependencies, but this is wrong. The checking in 'raco setup' doesn't
catch this because the files aren't compiled, but at a minimum it
depends on `unstable/debug` (currently a hidden part of
`typed-racket-lib`) and some portions of htdp that aren't declared.

This brings up (at least) 3 questions

- What is it ok for `racket-test` to depend on?  I'd like this set to
be small, so we can test the core without needing to build everything.
- Should we compile the contents of `racket-test` so that we get
dependency checking?
- Should parts of `racket-test` be split up?

I'd like to figure this out, but I don't have answers yet.

Sam