In cases like this I used to open a new window and use this plugin [0] to move them fast, because dragging tabs between windows seems very finicky to me in Firefox.
Hopefully with this update things will improve.
That and the keep-consuming-all-memory-until-all-memory-is-consumed switch, and the killing of GCLI (see: https://joindiaspora.com/posts/77a57160cf470136d1540218b70db...) which makes restarting FF far more fraught. Quite honestly, a "force quit" seems to be the most effective approach.