Multilevel deep nested generic classes support

Currently we don't support identifying specific type for nested classes, like so:

```java
public class GrandParent {
public Parent.Child stringAllTheWay() {
var parent = new Parent(value, "Hello");
return parent.new Child(value, "Hello", "World");
}
// ...
}
```

This will work though:

```java
public Parent.Child stringChild(S nestedValue) {
var parent = new Parent(value, nestedValue);
return parent.new Child(value, nestedValue, "World");
}
```

The summarizer must be updated to include these information. Related to dart-lang/native#706.