Port Perl 5 built-in times() to PIR

[dukeleto]

It would be nice to be able to have something like Perl 5's times() builtin in PIR for calculating user time:

       times   Returns a four‐element list giving the user and system times,
               in seconds, for this process and the children of this process.

                   ($user,$system,$cuser,$csystem) = times;

               In scalar context, "times" returns $user.

               Note that times for children are included only after they
               terminate.