This test caused problems because it relies on the at-spi services to
run. In addition it could trigger orca (screen reader) to be launched
as a side-effect of the dbus call to the screen-reader-enabled setting.
Instead just export QT_LINUX_ACCESSIBILITY_ALWAYS_ON to make sure that
accessibility will work. This means we won't test the dbus startup any
more, but the test will be reliable.
There is still a dbus call to org.a11y.Bus to launch the service in case
it's not running yet.
Task-number: QTBUG-27732
Task-number: QTBUG-44434
Change-Id: Idb86ed98ca4b47cb209027c8b41529e7e5285197
Reviewed-by: Caroline Chao <caroline.chao@theqtcompany.com>