This triggers a code path in Persistent Group Chats that causes a memory
leak. I'm adding this test now, so that we don't merge PGC without fixing
the memory leak first.
Tests are not actually ran on appveyor for now, since they all fault for
some reason. For now, we just build them. Also, some tests are disabled
on msvc entirely, because they don't even compile. We'll need to look
into those, later. They are disabled using `MSVC_DONT_BUILD`.
