Implement PhutilRequest parser

Summary:
If D6277 is the way to go, then this will be it's implementation.

Depends on D6277

Test Plan: Keep using the site

Reviewers: epriestley

CC: aran, Korvin

Maniphest Tasks: T3432

Differential Revision: https://secure.phabricator.com/D6278
Fix a mistakenly translated query from D6262

Summary: Ref T2222. I didn't translate this query properly; reproduce the original.

Test Plan: When viewing a revision with non-draft inline comments by a user other than the viewer, the inline comments now appear on the changesets themselves.

Reviewers: kawakami, btrahan, garoevans

Reviewed By: garoevans

CC: aran, mbishopim3

Maniphest Tasks: T2222

Differential Revision: https://secure.phabricator.com/D6281