IIFE inlining

[michaelficarra]

(function(){
  something();
  something();
})();

to

something();
something();

as long as the function

• does not refer to this or arguments (or new.target or super, I guess?)
• has no arguments
• does not contain a return - if it does, replace the return with evaluating the expression and a break? or just don't worry about it
• does not contain any conflicting variable declarations (which I guess means not doing this to IIFEs which are not contained in outer functions when the IIFE has a declaration).