Added a printout for the overall test execution time

Change-Id: I0aa19bf0749dde07ce7ececc3ae8fb4bc3cd21ff
Signed-off-by: Jan Medved <jmedved@cisco.com>
(cherry picked from commit f475ce5265377af26ee42fc722af24f46307821e)
Merge "Added a printout for the overall test execution time" into stable/helium