Fixes GROOVY-6924 (IncompatibleClassChangeError) and GROOVY-6926 (DGM#with not annotated)
   * Static compiler was trying to call setProperty on a class which doesn't implement GroovyObject
   * DGM#with didn't make use of @DelegatesTo, leading to special handling of "with"
   * carry implicit receiver information as well as property owner to the invocation writer
Fix unit test in order to have a constant closure class name