Find does not traverse ClassDeclarations superTypeParameters

When I'm searching for all `GenericTypeAnnotations`s find does not traverse the generics on a super class that a class extends.

```
class Foo extends Bar {}
```

It would not find Baz for example, even though it is a `GenericTypeAnnotation`.

Here's an example that highlights this, http://felix-kling.de/esprima_ast_explorer/#/odivoefENV/16