Skip the "Too Many Errors" error that is raised by JSHint.

Summary: If JSHint encounters too many errors (by default, more than 50) errors, then it quits prematurely and raises an additional (rather unhelpful) "Too Many Errors" error. We should just ignore this additional error.

Test Plan: Added a test case.

Reviewers: Blessed Reviewers, epriestley

Reviewed By: Blessed Reviewers, epriestley

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D9693