Refactor: cts: Drop CTSTest.templates

It's redundant. It's exactly the same as _cm.templates, except that
it's separate instance. Nothing modifies either instance after creation,
so it should be fine.

(Ideally this would be something like a const variable, so that the
templates can't be modified after instantiation.)

Signed-off-by: Reid Wahl <nrwahl@protonmail.com>