Need better CI for assignments

[dvanhorn]

Currently the CI explicitly omits (via info.rkt) running the compiler tests because these include assignment-specific tests that are intended to fail (until the assignment is completed). But this means that even tests that should pass, i.e. tests that don't include assignment features, aren't run and consequently we miss a bunch of bugs that could be easily caught.

The current organization doesn't lend itself well to splitting the tests into tests for the base language and the extension, but we should come up with something so that the compiler is tested before being released to students.

We also need to make sure that we're testing the printing code from the run-time since the C source isn't generated by Crook, so these files tend to bit-rot when not tested.

[pdarragh]

One of the features I'm planning for my autograder livrary/platform is the ability to more easily run individual sections of tests, so that should hopefully help with not failing due to implemented functionality.