Add testing shims to allow switching of app ops/permission backend Add a shim layer in between the AppOpsService/PermissionManagerService and their respective implementations. In these shims, include both the old and new implementations. Select which implementation to use based on deviceConfig. Also support running both, and comparing the outputs. Bug: 252886104 Test: manual Change-Id: Ibe420a1985b041816cb2d6e675761cffa6462f24