Rulesave: extra.buildable not always saved when it should
Split from #42695 reported by ddeanbrown:
Rulesave saves extra.buildable when its value is FALSE, i.e., it considers TRUE to be the default value that needs no saving. In S3_0 and later, the default is not always FALSE, but depends on is_extra_caused_by_worker_action(). Value of TRUE should be saved (as non-default) when extra has no worker action related cause.