Merge remote branch 'origin/bugfix/8564_snslivelistener_devicedescriptor_crash'
Refs #8563. Additional test for ADS.
Refs #8563. Re-factore bool() operator of ScopedWorkspace.

Now that we can be sure there can not be any null pointers in the
ADS, it becomes as simple as just checking whether workspace exists
in the ADS.
Merge branch 'feature/8563_scoped_ws_bool' into develop