Generate metadata for non-public base classes

In Java it is possible to call public method of non-public base class. Here is an example:

``` Java
class Base {
   public void method1() {
   }
}
public class Derived extends Base {
   public void method2() {
   }
}
...
Derived d = new Derived();
d.method1();
d.method2();
```

Currently the metadata generator doesn't generate metadata for `Base.method1`.
