Skip snapshot tests for non-Virtual A/B devices

The libsnapshot features are currently not used anywhere else than the
update system with Virtual A/B.
Ignore libsnapshot tests for devices that are not implementing this
feature.

Test: m, snapshot_test, OTA
Bug: 142513589
Change-Id: I4580bae5ed315f21501556eea062e6af1f982ab3
Signed-off-by: Alessio Balsini <balsini@google.com>
2 files changed