wrap-java: Generated @JavaInterfaces must have JavaObject base functions

The way we're generating Swift types for interfaces is problematic:

@JavaInterface("java.lang.reflect.TypeVariable", extends: Type.self)
public struct TypeVariable<D: AnyJavaObject> {
  @JavaMethod
  public func getGenericDeclaration() -> GenericDeclaration!
  
  @JavaMethod
  public func getAnnotatedBounds() -> [AnnotatedType?]

while we know we can call hashCode, equals and toString on those types... Lack of those on extracted types means we can't make ALL java types Hashable, which makes interfaces hard to work with -- and since a lot of java is interface based, that's not ideal.

It also makes our description->toString problematic.

Start in the wrap-java generation path responsible for Swift interface types such as TypeVariable. Trace how generated interfaces represent JavaObject behavior and determine how hashCode, equals, and toString should be exposed; done means generated interfaces provide those base functions and support the intended Hashable use.