Throw better exceptions from PhutilJSONParser.

Summary:
Ref T5297. Retrieve error context from JsonLintParsingException to provide a better exception message.

Depends on D9623.

Test Plan: Wrote and executed unit tests.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: epriestley, Korvin

Maniphest Tasks: T5297

Differential Revision: https://secure.phabricator.com/D9624