A couple of small decisions in discussion w/Martin: * If you have `Tests: foo` and `Features: test-name=bar`, warn and ignore the test-name feature.
* If you have multiple test-name features, e.g. `Features: test-name=a, test-name=b` warn and skip. * I want the feature name to match the command line option, but inconsistent with the other autopkgtest options, we have --testname. For consistency, this should be called --test-name, so let's support --test-name as an alias and deprecate --testname, with eventual hiding and/or removal some time later.