As autotests pass, we can also move all existing
Ubuntu 14.04 configurations to run on a more recent
Ubuntu 16.04.

Task-number: QTQAINFRA-1101
Change-Id: I99c4f674dc48521c66ac579c6bb1b5396c282131
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Simo Fält <simo.falt@qt.io>