Python 3.9 dropped isAlive() so use the preferred is_alive().
(From OE-Core rev: f101408bd43a5d41cb1710a7a848370292f84290)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 9bb06428cbb2ac0f3d98a1696f050d3393385503)
Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>