[1.2.X]. Convert m2m_recursive tests to unittests. We have always been at...

[1.2.X].  Convert m2m_recursive tests to unittests.  We have always been at war with doctests.  Backport of [14082].

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@14083 bcc190cf-cafb-0310-a4f2-bffc1f526a37