on linux32 we run reftests, but hidden, there is a perma fail test in R2: https://treeherder.mozilla.org/#/jobs?repo=autoland&revision=851a50989291df2d276d3094683c30feea32cf3f&exclusion_profile=false&filter-searchStr=linux%20r2 in building a docker image to run all linux32 tests via taskcluster, I see the same failure (although we are on ubuntu16.04 there): https://treeherder.mozilla.org/#/jobs?repo=try&revision=e3102a63b0db9fafef52ab6cf34d2ce82ab89bb4&selectedJob=31587994&filter-searchStr=r8 as it stands, this is the only perma fail test on linux32 in buildbot, and it seems to be following us to taskcluster.

I looked for this bug and I cannot find on any trunk trees any sign that we run linux32 reftest, neither as hidden or tier3. To me, this is something that we need to not spend time on and can revisit when we want to run reftests on linux32.

They're not running on buildbot because they were turned off by me in bug 1317568 because they were permafailing and wasting resources due to the GTK3 issues that were wontfix on buildbot infra. I don't think that decision should impact this bug because the buildbot wontfix was specifically because 16.04-based Taskcluster was the "real" fix for the problem.