tests: Move prog_args_save() later
Move our DRM test fixture setup later, where we already have a bunch of per-backend splits, so we can choose to skip our tests at the right time.
Doing this allows us to skip DRM tests with no memory leaks.
@pq fine, I lied when I said I wasn't going to do this. Realised whilst walking home what I needed to make it work.
cc @leandrohrb