Apparently we have some flutter driver tests in the repo; we don't currently run drive-examples on any platform. We also don't build examples on web or any of the desktop platforms.

We should add all of that to the CI so that anything that's added to the repo actually runs.

(I'll also audit for other differences; I happened to find today that readme-check was never turned on, and there may be other new checks that haven't been enabled for the packages repo.)