Add diagnostic groups for goog.provide/goog.require checks
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=49712078
Automated g4 rollback.

*** Reason for rollback ***

split cl: this is the conservative part and this passes

*** Original change description ***

Automated g4 rollback.

*** Reason for rollback ***

breakages

*** Original change description ***

Two more changes to RemoveUnusedClassProperties
1) Legacy Closure style code often defines value on the prototype, we want to remove those if it is the only other property set. Previously we would leave them and the RemoveUnusedPrototypeProperties pass would remove them, but now that we would otherwise back off in the face of them we want to remove them.
2) If someone
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=49713871