codeintel: Stop infinitely processing the same batch of unknown commits
Created by: efritz
Ok so this is obvious in retrospect. This is actually the same class of bug I reported in the Go runtime.
We keep processing a batch of (repository_id, commits) that are ALL unknown to gitserver because we don't mark any of them as being processed. We now insert a sentinel value of '-infinity' (which is a valid time in Postgres!) and skip that on the reading side.