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