Object#inspect must be compatible with default external encoding
CRuby #4869 is not fixed on 1.9.2
CRuby Redmine #5864 is fixed on 1.9.3 and use correct encoding names
m::N with module sentence returns its name

The module sentence registers its ID.
In this case, the module knows that it is called as "N" and its outer module.
3rd argument of IO.new is 1.9.3 or later