Bug 1786291 has turned off the ESR91 jobs, which means no more semantic indexing. (Technically, we could continue to survive off of the last run's artifacts but there's a problem with corrupted JSON that is now tripping our new warnings, so it's simplest to turn off ESR91 now.)

comm-esr91 never had semantic indexing and so it doesn't need anything turned off.

I'm not moving the jobs across indexers because things are fairly nicely balanced right now for the livegrep index memory use, and that won't change when we turn off semantic indexing (although the crossref will shrink a ton).