ActiveSubsciptionsListenerTest converted to junit

note that this class contains a state machine of the subscription
information cache. The mock subscription manager must present
subscriptions in order for an update intent to result in a change
notifcation.

Bug: 175389659
Test: atest -c ActiveSubsciptionsListenerTest
Change-Id: I8cd2bd5d5b7b1539f421822ba77ed3d8e0ac493b