Prune abandoned autofill sessions
Regularly check if the sessions are still valid and clear the ones that
are not.
Test: 1. Started session in dialer
2. Home button (dialer goes in background)
3. kill -9 dialer
4. Wait 30 seconds
5. Start session is messenger
6. dialer session stays
1. Started session in dialer
2. Home button (dialer goes in background)
3. kill -9 dialer
4. Swipe dialer from recents
5. Wait 30 seconds
5. Start session is messenger
6. dialer session is removed
Fixes:
38005472
Change-Id: I8199ce44777b313141ee1eab6c8de5ad5089474a