Stop duplicating per-segment work across segment partitions

With the introduction of intra-segment concurrency support (see #13542), the `IndexSearcher` is able to parallelize search across partitions of segments. Some of our queries, like `PointRangeQuery`, perform per-segment computation ahead of time, that is currently not shared across segment partitions, but rather duplicated across them.

This makes intra-segment concurrency not appealing for those queries, which we should look at addressing. If we can share such computation across segment partitions, we can likely enable intra-segment slicing by default and ensure that intra-segment concurrency is beneficial for all queries.

Start by reading IndexSearcher and PointRangeQuery, then review issue #13542 for the intra-segment partitioning design. Trace where per-segment computation is performed for partitioned searches and determine how it could be shared; done means the work is no longer duplicated across partitions and intra-segment concurrency is beneficial for these queries.

Written by the indexing model from the issue text.