Bug 1045948 - IonMonkey: Obviate LAllocation's tag bit. r=bhackett
Bug 1045948 - IonMonkey: Eliminate LDefintion::PASSTHROUGH. r=bhackett
Bug 1045948 - IonMonkey: Make bogus LAllocations have an all-zeros bit pattern. r=bhackett
Bug 1045948 - IonMonkey: Make LAllocation's data unsigned r=bhackett