[NEW TYPE INFERENCE] Optimize ObjectType.isInhabitable for speed.
-------------
Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=73349062
[NEW TYPE INFERENCE] Add unit test for github issue 583.
-------------
Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=73391021