codeintel: More intelligently read from result chunks

Created by: efritz

Currently we call Store.locations in the lsifstore backend frequently. We've tried to reduce the amount of data we need to pull back by adding limit/offset control in https://github.com/sourcegraph/sourcegraph/issues/18250. This is only a partial measure.

We need to additionally only read result chunks that can contain items we will not immediately throw out because the results are out-of-page.