JS: more implied receiver steps

[asgerf]

Propagates this into functions that are installed on objects in a non-trivial way, e.g:

function fooFactoryFactory() {
    return function fooFactory() {
        return function foo() {
            /** calls:F.member */
            this.member();
        }
    }
}

function F() {
    this.foo = fooFactoryFactory()();
}