Object literal treatment under ADVANCED_OPTIMIZATION is not clear

It's unclear how object literals are treated under ADVANCED_OPTIMIZATION. The [tutorial page that explains ADVANCED_OPTIMIZATION](https://developers.google.com/closure/compiler/docs/api-tutorial3) is incomplete.

I believe the following code does not preserve the 'preserveMe' property:

``` js
var x = {preserveMe: false};
```

However, this code does:

``` js
var x = {'preserveMe': false};
```

Please clarify the compilation semantics in the docs.