Bug 939581 part 1.  Factor out MCallDOMNative from MCall.  r=efaust,jandem
Bug 939581 part 2.  Don't create resume points for non-effectful methods (which currently just means DOM methods), on the assumption that such methods have no side-effects and throw deterministically based on thisval and arguments.  r=jandem,efaust
Bug 939581 part 3.  Mark DOM calls as movable as needed and allow them to be CSE'd.  r=efaust