I believe this isn't an issue with the test itself, but some new behaviour introduced in bug 1583495. There is a fix underway in bug 1583993, which will fix this test failure.
Bug 1583708 Comment 2 Edit History
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I believe this isn't an issue with the test itself, but some new behaviour introduced in bug 1583495. 1583495 landed right after bug 1579004. There is a fix underway in bug 1583993, which will fix this test failure.