Fix infinite loop in renderAccessDenied()

Summary:
Fixes T8727. When I added setParentQuery(), I increased the cache hit rate but also accidentally propagated policy exception settings.

Instead, make the policy exception beahvior explicit: no exceptions should be raised when querying handles.

Test Plan: Will test production.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T8727

Differential Revision: https://secure.phabricator.com/D13489