Message 131148 - Python tracker

Benjamin, I would like some way to know when our tests achieve 100% coverage because otherwise I will keep coming back to this module to add more tests and have to re-discover code that is not CPython relevant.  But for now I have removed the pragmas.

The attached patch also changes assertIs() and assertIsNot(), and uses self.fail() instead of the exception inside of "support". Thanks for those pointers!