8076543: Add @modules as needed to the langtools tests
Reviewed-by: jjg, shurailine

8050430: Provided new utility visitors supporting SourceVersion.RELEASE_9
Reviewed-by: jjg

8005282: Use @library tag with non-relative path for javac tests
Reviewed-by: jjg

6505047: javax.lang.model.element.Element.getEnclosingElement() doesn't return null for type parameter
Reviewed-by: darcy