Add some basic tests for some of the globals noted in #12292

This is by no means complete (a lot of modules get __low__ or __env__ from their callers), but this will help catch some of the problems where we change the loader and the magic stops.

IMO we kinda need to overhaul the loader, and break out the module load, __virt__ running, packing of globals, and caching into seperate pieces
Merge pull request #13619 from jacksontj/develop

Add some basic tests for some of the globals noted in #12292