I discussed this with triage leads and Sheriffs and there's agreement to do a cleanup of these bugs. This could be done with a bulk change, but I'd like to avoid creating a giant storm of bugspam. Query I'm using: https://mzl.la/2c3Gazf

All done.

Committed to repo for posterity. To https://github.com/mozilla-bteam/bmo.git 37dd5ba..bb40800 master -> master

If you ever wind up needing to do any bulk action to intermittent-failure bugs again, it would be better to do so without changing the last modified date: treeherder shows bug suggestions for test failures in two groups: open_recent containing open bugs modified in the last 90 days, and hidden behind a "Show/Hide more" link an all_others group that includes closed bugs and open bugs with a last modified date more than 90 days ago. For the next 90 days after 2016-09-01, open_recent is going to be a whole lot bigger and all_others a whole lot smaller.

This unfortunately caused OrangeFactor to start giving HTTP 500s in bug 1301107, since the BzAPI query now fails.