Can't use goog.reflect.object/objectProperty from es6 module.

I see that `objectProperty` and `object` are available in closure-compiler/lib/reflect.js. However I do not see any way to use these from an es6 module. I tried adding these to goog.js and using it like this:
```
import * as goog from 'goog.js'
const x = goog.reflect.objectProperty(...)
```

However goog.js only seems to work with properties of goog itself, not two-levels deep.
I end up with an ast like `(GETPROPERTY objectProperty (NAME goog$reflect))`, but the `isPropertyRenameFunction` method only allows one of these:
```
(NAME JSCompiler_renameProperty)
(GETPROP objectProperty (GETPROP reflect (NAME goog)))
(NAME goog$reflect$objectProperty)
```