anchor.diff:  
         int i = _HashBase._firstProbe(fullHash, sizeMask);
         int pair = index[i];
  +      int probeDistance = 1;
         while (pair != _HashBase._UNUSED_PAIR) {
           assert(pair != _HashBase._DELETED_PAIR);
   
  
positive.code:     int i = _HashBase._firstProbe(fullHash, sizeMask);
      int firstDeleted = -1;
      int pair = index[i];
      while (pair != _HashBase._UNUSED_PAIR) {
        if (pair == _HashBase._DELETED_PAIR) {
          if (firstDeleted < 0) {
  
negative.code:           }
          }
        }
        i = _HashBase._nextProbe(i, probeDistance, sizeMask);
        probeDistance += 1;
        pair = _index[i];
      }
      return null;
  