By compiling only the script and ignoring inner functions until they are called, replacing them with trampolines, we can improve startup time.

This also makes it possible to specialize inner functions on callsite instead of generating an object parameter -> object return value function. See e.g. crypto#am3 for potential large speedup.

Downside is that we generate more classes. Lazy heuristic should probably be tweaked so we generate several functions at once or something.