codeintel: py3: ignore trailing comma when cleaning args
http://bugs.activestate.com/show_bug.cgi?id=101868

This also imports the Python 2 defn tests to Python 3 to have _some_
coverage... Not sure how useful that is in practice.
The newly added test is definitely Python 3 only, though

(integrated from komodo (trunk) change 84164 by marky)

git-svn-id: http://svn.openkomodo.com/repos/openkomodo/trunk@14266 b87d16e7-d29f-4ee1-b5ec-817d645d335f