gh-87587: Fix os.device_encoding() for any console on Windows (GH-155410)

It was hard coded to map file descriptors 0, 1 and 2 to the console code
page, but a console can be opened as any file descriptor, and other
character devices, like NUL, are not consoles.

The file handle is now queried.  The UTF-8 code page is also now reported
as "utf-8" instead of "cp65001".