Just to update, I applied for an unblock (#986915) for 4.8.0-2, which * runs the tests against installed code (instead of the source tree) * blacklists the remaining known flaky tests (appears to match the list Lukas provided)
The changes are in git but I haven't uploaded yet (pending approval) - if I haven't heard by 2021-04-16 I will probably upload anyway, as I'll be offline for a week after that, and I _hope_ the changes are fairly uncontriversial. I didn't include all of Lukas' changes - race condition, I'd already made the unblock request before checking this bug again, but I'll try and merge the ubuntu diff after the release.
