R1:c16c920f941a

Remove setTimeout() hacks for Javelin behavior initialization

Summary:
- Prioritize higher-priority behaviors on the server.
- Remove setTimeout() hacks.

Test Plan: Loaded Differential, didn't get CSRF races for comment previews.

Reviewers: aran, jg, cpojer

Reviewed By: jg

CC: btrahan, jungejason, aran, epriestley, jg

Differential Revision: 1183