code: public static <T> List<T> dropRight(List<T> self, int num) {
          return (List<T>) dropRight((Iterable<T>) self, num);
      }
docs: Drops the given number of elements from the tail of this List.
  <pre class="groovyTestCase">
  def strings = [ 'a', 'b', 'c' ]
  assert strings.dropRight( 0 ) == [ 'a', 'b', 'c' ]
  assert strings.dropRight( 2 ) == [ 'a' ]
  assert strings.dropRight( 5 ) == []
  </pre>
  
  @param self the original List
  @param num  the number of elements to drop from this List
  @return a List consisting of all the elements of this List minus the last <code>num</code> elements,
  or an empty List if it has less then <code>num</code> elements.
  @since 2.4.0