null return from ClassVisitor.visitAnnotation causes NullPointerException
The documentation implies that a null AnnotationVisitor can be returned from
ClassVisitor.visitAnnotation (to skip processing annotation values); doing so
causes a NullPointerException.
ClassReader.readAnnotationValues is called with the results of
ClassVisitor.visitAnnotation, without any checks around or within of a null
AnnotationVisitor.
I've worked around this by returning a new EmptyVisitor.