I have triggered an additional build on master to see if the problem persistent https://travis-ci.org/matplotlib/matplotlib/builds/299098042
Update: Yes, it is.

Specifically, it broke polar plot tests. Originally it was passing, so either the tests are new, or the changes in polar plotting in the interim are interacting badly with this change. Attn @QuLogic

Some of the tests are old, so it's probably something in the new polar options that is broken. I remember having to add seemingly-superfluous reset_ticks, so there's probably some other path that's missing the right trigger.