Base element's static method with nocollapse shouldn't be collapsed in subclasses.

In this scenario:

```
class BaseClass {
/** @nocollapse */
static getSomething() {}
}

class SubClass {
/** @override */
static getSomething() {}
}
```

The `SubClass`'s `getSomething` static method gets collapsed and removed. However, an overriden static method like this should stay since it's kept in the superclass.