Throw TypeError when trying to serialize native built-in functions

[ericf]

This changes the serialization process of functions to throw when a native built-in function is trying to be serialized.

[caridy]

+1

[clarle]

Weird edge case, but might also want to check for function Empty() {} too in case someone decides to try to serialize Function.prototype.

[ericf]

@clarle I'm not worried about that one since it's valid JavaScript. But in the future the prototypes of built-ins may get tricky to deal with as they will stop being instances of their own constructors.

The reason I wrap everything in an IIFE is to keep any named function declarations from hoisting out into another (global) scope.