Don't enable C in the tests

[zachcran]

Is your feature request related to a problem? Please describe.
No. I just saw this while working on #110 and figured I would suggest it.

Describe the solution you'd like
In the template file for the CMakeLists.txt of each test, the LANGUAGES of the project() command is set to C so "dummy libraries don't complain about not having a linkage language". I'm pretty sure this can be set to NONE to avoid enabling unnecessary languages in the tests.

Describe alternatives you've considered
Leave it as it is.

Additional context
I'm not sure what happens if there is not a C compiler on the system, nor do I know if fix would save any time. It just seems unnecessary since unit tests for CMake do not need C and you can set it to NONE without CMake complaining (as far as I could tell).