login: use close_range() system call when possible

login: use close_range() system call when possible

This system call was added while back, but does not have glibc support yet.
Lets try to use the new facility early on.  The promise in reference link is
that the new call is faster, and works when /proc is not mounted.

Reference: https://lwn.net/Articles/789000/
Reference: https://lwn.net/Articles/789023/
Reference: https://kernelnewbies.org/LinuxChanges#Linux_5.9.New_close_range.28.29_system_call_for_easier_closing_of_file_descriptors
Signed-off-by: Sami Kerola <kerolasa@iki.fi>