Summary:
1. When testing major changes to the differ, it can be useful to have more verbose logging.
2. On Android, since asserts don't fire yet, I log which asserts are failing.
Should have no impact on any builds unless you manually set the macro here, and it will have no impact on production builds regardless.
Changelog: [Internal]
Reviewed By: shergin
Differential Revision: D23257859
fbshipit-source-id: 94a8e74ece8023064de0f2203db6074975f8f1f0