Don't put objects into the query workspace by default

Summary:
Ref T8731. I think the issue is that some ProjectQuery (without needImages()) populates the query workspace, then the "real" one hits the workspace.

Instead, only populate the workspace from ObjectQuery, so we know that objects in the workspace always have whatever ObjectQuery attaches to them.

Test Plan: Verified this didn't destroy the cache hitrate, but I can't repro the original issue locally per se.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: chad, epriestley

Maniphest Tasks: T8731

Differential Revision: https://secure.phabricator.com/D13516