Convert to ES2015 class do not recognize inheritance

Issue Type: Bug

function Derived() {
  Base.call(this, /*some base args*/);
  /* some other constructor work */
};
Derived.prototype = new Base();
Derived.prototype.constructor = Derived;

must be converted to

class Derived extends Base {
  constructor() {
    super(/*some base args*/);
    /* some other constructor work */
  }
}

Right now it converted to

class Derived {
  constructor() {
    Base.call(this, /*some base args*/);
    /* some other constructor work */
  }
}
;
Derived.prototype = new Base();
Derived.prototype.constructor = Derived;

VS Code version: Code 1.36.1 (2213894ea0415ee8c85c5eea0d0ff81ecc191529, 2019-07-08T22:59:35.033Z)
OS version: Windows_NT x64 10.0.17134

Reproduce the conversion in VS Code with the function-based Derived and Base example from the report, then trace the JavaScript-to-ES2015 class conversion entry point. Done means the result uses class Derived extends Base and super(...) while preserving the other constructor work, rather than leaving prototype assignments behind.