Fixed #7786 -- Removed some tests from running when using Python 2.3.

The problem being "hidden" here is not serious. It won't affect correct code
and only gives a different failure mode for incorrect code. The moral is: don't
write incorrect code.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@7939 bcc190cf-cafb-0310-a4f2-bffc1f526a37