win32.c: manage reverse video

* win32/win32.c (constat_attr): manage reverse video internally
  since Windows console window does not manage it.  based on the
  patch by white leaf in [ruby-dev:48483].  [Bug #10158]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47241 b2dd03c8-39d4-4d8f-98ff-823fe69b080e