Bug 869996 - Implement Set.prototype.{keys, values, entries}. r=jorendorff.

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extra : rebase_source : 6d978d49d2fb696162b1cef5b643a209a01a4711
Bug 875433 - Array.prototype.iterator is the same function object as .values. r=jorendorff.

--HG--
extra : rebase_source : 0b9b93bd796ba2c528b89c377b8aac922631ec98
Bug 877639 - Switch some code in frontend/FoldConstants.cpp from getOp() to getKind(). r=jwalden.

--HG--
extra : rebase_source : 97c448dc52660fc0257d81730b1c07eb2b89df40
Bug 858060 - Throw SyntaxError on module syntax. Fix bogus assertion. r=jorendorff.

--HG--
extra : rebase_source : ea25ab9fa70ff070ab85a5d4187d9b7312817557