fix(tests): fix broken tests on Internet Explorer 9

Includes:
  - The runner was failing when accessing the `dataset` property of a dom
    object, which is not supported by IE9.
  - The `utils.inspect` tests was failing because in IE9 function's name
    look like `function name() {}`.
  - The `Function::setter` and `Function::getter` tests was failing because
    IE9 doesn't support the `__proto__` property. The standard `Object.getPrototypeOf`
    function is used in priority.