R1:c39b64d963db

Improve handle loading semantics for tokenizers

Summary:
Ref T7689. Fixes T7688. When there are a bunch of tokenizers with different values of the same object type (e.g. 5 tokenizers with users a, b, c, d, e) we currently issue 5 separate queries to load their handles.

Improve this behavior in the common case so we can usually batch these loads.

Test Plan:
- In Maniphest, set the various search fields to different values.
- Used DarkConsole to examine query plan.
- Saw fewer queries after patch…