break label compiles with error

[hkollmann]

From qxl/demobrowser/TreeDataHandler.js

    {
      var classname = "";
      var tests = [];

      classloop:
      for (var i=0; i<this.tmap.length; i++)
      {
        for (var j=0; j<this.tmap[i].tests.length; j++)
        {
          if (this.tmap[i].tests[j] == node)
          {
            classname = this.tmap[i].classname;
            break classloop;
          }
        }
      }

      return classname;
    },

gets qxl.demobrowser.TreeDataHandler: [411,18] Unresolved use of symbol classloop

[hkollmann]

Done with #569