Minor cleanups in AmbiguateProperties.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=82242628
[NEW TYPE INFERENCE] Understand superClass_ property of ctors
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=82270198
Treat "?T" the same as "T|null", even if T is a template type.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=82274926