win32/file.c: share functions with win32.c

* win32/file.c (rb_file_expand_path_internal, rb_file_load_ok):
  use functions defined in win32/win32.c.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47117 b2dd03c8-39d4-4d8f-98ff-823fe69b080e