Object created with Object.create not dead code eliminated

When creating an object through `Object.create` and adding a property to it, it will not be removed in ADVANCED mode, even if nothing references it.

**Not** removed:

``` javascript
/** @type {!Object} */
const foo = Object.create(null); // or Object.create({});
foo.prop = 2;
```

Removed:

``` javascript
/** @type {!Object} */
const bar = {};
bar.prop = 2;
```