Make test_warnings play nice with regrtest -R:: now that regrtest doesn't always reload the module (specifically, it doesn't reload if the module has a 'test_main'.)
Make test_warnings play nice with regrtest -R:: now that regrtest doesn't
always reload the module (specifically, it doesn't reload if the module has
a 'test_main'.)

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator