A long standing task is to show the job execution time, instead of the
sum of tests execution time.  After some major work, this is now
possible.

This change adds the job execution time to the human interface UI, in
addition to the test execution time.  Some users may prefer the job
execution time alone, while others may prefer all the time statistics
on a single line.

Since we cannot please everyone, this version just adds it.  I believe
UI tweaks can follow.
Signed-off-by: NCleber Rosa <crosa@redhat.com>