Test case for bug 28956 IBM JDK 1.3.1 reports methods as abstract causing problems when generating enhanced classes 

http://issues.apache.org/bugzilla/show_bug.cgi?id=28956

Check that we can defeat the logic that checks for unimplemented abstract methods.

This appears necessary when using IBM JDK 1.3.1 which appears to report
concrete methods of abstract classes as abstract.