Avocado has until now shown very simplified time information for jobs,
and some could even say unprecise or just plain incorrect.

The fact is that the time displayed in the UI (HumanResult) and also
on the various other supported formats is the sum of the run time of
individual tests.

The problem with that is tha a job may include other actions that can
take time, from little to substancial amounts.  This makes it clear
that a job that say, took 30 seconds to run (although not displayed at
this point), spent only 20 seconds actually running tests.
Signed-off-by: NCleber Rosa <crosa@redhat.com>