Write an analysis test for `whl_library_targets`

[aignas]

This is a followup task from #3059.

The main idea would be to rewrite or write additional analysis tests that cover the glob usage within the whl_library_targets macro.

[rickeylev]

I have an unpublished draft that adds some tests for 3059. The two key things it does are implement a more transparent mock (function that records/replays) and injects create_inits via the rules struct.

An analysis mock would be cleaner, though. If something isn't directly exposed, we could have an extra target hidden behind the --visible_for_testing flag with info about what the macro phase did.

[aignas]

All of this sounds good to me. The way that it is tested today feels a little clumsy, but it did the job when I was implementing all of it.

Thanks for posting some ideas here.