Expire old bitmaps as owning app

It's possible for an old notification to have been posted by a
now-revoked notification delegate. we should still expire
bitmaps in this case

Test: manual: modify CTS testNotificationDelegate_grantAndRevoke to
grant / post / revoke / wait and set NMS to constantly expire - ensure
no crash and notification updated properly in the shade
Test: NotificationManagerServiceTest
Fixes: 374295673
Flag: EXEMPT bugfix

Change-Id: Ieeea79d4e78b072a68551dcc9e34c493faca9373