As of [this try push](https://treeherder.mozilla.org/#/jobs?repo=try&group_state=expanded&selectedJob=231969983&revision=33a2fa7bf0d27184a606318f80ec00d5ef2387d8) it appears that this test is either no longer running or not failing. I'm willing to close this bug as resolved - fixed, unless you would like to still look into this.
Bug 1525415 Comment 15 Edit History
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As of [this try push](https://treeherder.mozilla.org/#/jobs?repo=try&group_state=expanded&selectedJob=231969983&revision=33a2fa7bf0d27184a606318f80ec00d5ef2387d8) it appears that this test is either no longer running or not failing. I'm willing to close this bug as resolved - fixed, unless you would like to still look into this. Edit: this test began failing again from subsequent try pushes, so this bug will likely have to remain open.