Allow restoring of apps that rotated key

Restoring of apps that rotated key wouldn't be possible due to
explicit signature matching.
Amend signature matching strategies to take into account
apps that have rotated key.

Test: atest frameworks/base/services/tests/servicestests/src/com/android/server/backup/utils/AppBackupUtilsTest.java
Test: atest frameworks/base/services/tests/servicestests/src/com/android/server/pm/backup/BackupUtilsTest.java
Test: m -j RunFrameworksServicesRoboTests
Test: runtest -p com.android.server.backup frameworks-services
Bug: 64686581
Bug: 34345052
Change-Id: I91b5ae0afb6f2714ceae02b4d4dc202d6cd4fe4e