Fix performance issue around resolving lazy constants in JIT-compiled AVM2 code

Improves performance on V8 Richards by ~8x.
Bug 1105480 - Make AVM1 MovieClips mouse-transparent as long as they don't have button-related event handlers
Merge pull request #1914 from tschneidereit/master

Bug 1105480 - Make AVM1 MovieClips mouse-transparent as long as they don't have button-related event handlers