Improve serialization of bound functions with circular references

[overlookmotel]

Current serialization of functions with circular references is very verbose:

Input:

export default function f() {}
f.bound = f.bind({});

Serialized output:

const bindingBound_f = (() => {
    let bound;
    return [
      (...vars) => bound(...vars),
      _bound => bound = _bound
    ];
  })(),
  Object$0 = Object,
  f = Object$0.assign(
    function f() {},
    {
      bound: Object$0.defineProperties(
        bindingBound_f[0],
        {name: {value: "bound f"}}
      )
    }
  );
bindingBound_f[1](f.bind({}));
export default f;

This works, but could be a great deal shorter. Output should be identical to the input.

[overlookmotel]

This will be easier to solve once two-phase serialization is implemented (#426).