Make extern validation suppressible so I can land the ES6 externs which uses:

foo[symbol] = ...
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=77221403
[NEW TYPE INFERENCE] Small cleanups.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=77222243
Add notify callback parameters to angular.$q.Promise externs.

Reference documentation: https://code.angularjs.org/1.3.0-rc.2/docs/api/ng/service/$q
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=77238933
Open-source the lint checks unit tests
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=77266742
Flesh out Map/Set/WeakMap/WeakSet in preparation for moving them to the standard externs.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=77270963