function directiveIsMultiElement(name) {
      if (hasDirectives.hasOwnProperty(name)) {
        for (var directive, directives = $injector.get(name + Suffix),
            i = 0, ii = directives.length; i < ii; i++) {
          directive = directives[i];
          if (directive.multiElement) {
            return true;
          }
        }
      }
      return false;
    }
looks up the directive and returns true if it is a multi-element directive,
and therefore requires DOM nodes between -start and -end markers to be grouped
together.

@param {string} name name of the directive to look up.
@returns true if directive was registered as multi-element.