Bug 456852 - different runtime errors when -Dforcemir set in acceptance test run (r+stejohns,lhansen)
Bug 456852 - different runtime errors when -Dforcemir set in acceptance test run (r+stejohns,lhansen)

The change removes an explicit check for a constructor prior to calling
ctor->construct().  It then relies on the C++ virtual override of ScriptObject
to route the call correctly and raise an exception if needed.

pfgenyun/tamarin-redux,pfgenyun/tamarin-redux,pnkfelix/tamarin-redux,pfgenyun/tamarin-redux,pnkfelix/tamarin-redux,pnkfelix/tamarin-redux,pnkfelix/tamarin-redux,pnkfelix/tamarin-redux,pfgenyun/tamarin-redux,pfgenyun/tamarin-redux,pnkfelix/tamarin-redux,pfgenyun/tamarin-redux,pfgenyun/tamarin-redux,pfgenyun/tamarin-redux,pnkfelix/tamarin-redux