Bug 901761 - Part 1: Pass slice register to OutOfLineNewGCThingPar and refactor volatile register saving. (r=nmatsakis)
Bug 901761 - Part 2: Support CreateThisWithTemplate. (r=nmatsakis)
Bug 903193 - Part 1: Make GC barriers only assert CurrentThreadCanAccessZone if the zone actually needs barrier. (r=bhackett)
Bug 903193 - Part 2: Refactor isThreadLocal to ThreadSafeContext. (r=bhackett)
Bug 903193 - Part 3: Refactor methods that ensure dense elements. (r=bhackett)
Bug 903193 - Part 4: Add ability to do read only lookup on the Shape tree. (r=bhackett)
Bug 903193 - Part 5: Refactor SetPropertyHelper and friends to have a thread local variant. (r=bhackett)
Bug 903193 - Part 6: Add ParallelExecution path to ArraySetLength. (r=bhackett)
Bug 903193 - Part 7: Replace PushPar use in Ion with SetElementPar. (r=nmatsakis)