I think this issue should be considered a test environment error.  Since this buildbot is set up in an environment where it is "running headless", that is to say the tests are run under a username that is not logged in to the window server, we should not be trying to run GUI tests there, in particular Tkinter tests.  Yes, in a better world, Aqua TK on OS X should not crash in this situation but it is not a Python bug that it does and it's a bit of a hassle to workaround the Tk bug by trying to determine whether the interpreter is indeed running under a user id that is currently also logged in as the primary GUI user.  Also note that there has been no update on the status of the Tk bug that Ronald filed a year ago; not surprisingly, it's not considered an important issue by the project and it's likely not that important for them to make the effort to fix it.  In the real world, this situation does not happen; you would only be running Tkinter stuff if you are logged in as the current GUI user and then the test does not crash.  So, for this and any other OS X buildbot "running headless", the buildbot configuration should be changed to skip GUI tests:

   make buildbottest TESTOPTS='-uall,-gui'

Can someone with access to the buildbot configuration make that change and ensure the crash goes away?