Update Core Reflection for Type Annotations to match latest spec

1) Javadoc and implementation of j.l.reflect.AnnotatedType and friends needs to be updated and clarified with regard to returned values and null

In general:

- If the Type or Type[] returning methods (getGeneric*, get*Bounds, etc) does not return 'null', the version returning an AnnotatedType (getAnnotated*, getAnnotated*Bounds etc) should not return 'null'.

- There should be a preference for returning "empty" AnnotatedType instances and 0-length AnnotatedType arrays.

2) Additional clarifications in the javadoc may be needed to match the latest spec, such as saying in the interface-level javadoc that:

- AnnotatedType represents the _potentially annotated_use of ...
- AnnotatedArrayType represents the _potentially annotated_ use of ...
- AnnotatedParameterizedType represents the _potentially annotated_ use of ...
- AnnotatedTypeVariable represents the _potentially annotated_ use of ...
- AnnotatedWildcardType represents the _potentially annotated_ use of ...