How to avoid issue about delete method in rbtree

[thongpham1412]

  # if key is not present.
  #
  # !!! Warning !!! There is a currently a bug in the delete method that occurs rarely
  # but often enough, especially in large datasets. It is currently under investigation.
  #
  # Complexity: O(log n)
  #
  #   map = Containers::TreeMap.new
  #   map.push("MA", "Massachusetts")
  #   map.push("GA", "Georgia")
  #   map.min_key #=> "GA"```