Does what it says on the can.
This is a follow up to #9472. Now that we have a control .lib, we can add tests for it.
Unfortunately, the `TermControl` itself is a horrible mess. So this new unittest lib is empty for now. I'm working on actual tests as a part of #6842, but this PR is here to keep the diffs smaller.
Also, apparently `server.vcxproj` had the wrong GUID in it.
* [x] I work here
* [x] Adds tests