### Example

  ```ruby
  # example.rb
  max32 = 2**30 - 1 + 2**30
  min32 = -max32-1
  [max32, max32+1, min32, min32-1].each{|n| p [n, n.class]}
  ```

#### Before this patch:

  ```
  $ bin/mruby example.rb
  [2147483647, Float]
  [2147483648, Float]
  [-2147483648, Float]
  [-2147483649, Float]
  ```

#### After this patch:

  ```
  $ bin/mruby example.rb
  [2147483647, Fixnum]
  [2147483648, Float]
  [-2147483648, Fixnum]
  [-2147483649, Float]
  ```