non-testing tests

[mcepl]

We have many many tests like:

    def test_validation_problems_for_changing_builtin_types(self):
        mod1 = testutils.create_module(self.project, 'mod1')
        mod1.write('l = []\nl.append("")\n')
        self.pycore.analyze_module(mod1)

        mod1.write('l = {}\nv = l["key"]\n')
        pymod1 = self.pycore.resource_to_pyobject(mod1)  # noqa
        var = pymod1['v'].get_object()

They actually don't test anything, only that the run code won’t crash, but even if it doesn’t generate any (or faulty) results, it would pass.