codeintel: Add more tests to python 3.
http://bugs.activestate.com/show_bug.cgi?id=101782

Note that this changes codeintel's Environment class to use a snapshot of
os.environ instead of doing it live.

(integrated from komodo (trunk) change 84188 by marky)

git-svn-id: http://svn.openkomodo.com/repos/openkomodo/trunk@14273 b87d16e7-d29f-4ee1-b5ec-817d645d335f