Generic infrastructure for detecting kernel modules [for ATF/Kyua]?

[Garrett Cooper]

Hello Julio, et al!
    The EMC Isilon tests have some assumptions as to what drivers are
loaded in the tests, and in order to bypass a lot of failed tests, I
figured it would be nice to have something like 'require.device
"aio"', etc in the Kyuafile/tests.
    I was wondering where FreeBSD-specific test infrastructure should
go -- in the port(s) or in the base system? Should it be in ATF or
Kyua or both?
Thank you :)!
-Garrett