Allow any actor when target package is debuggable

Also adds comprehensive tests for ActorState in overlayable
actor enforcement. These tests work by mirroring the logic
branches in the actual method, but using test data instead.

This technically doesn't run every combination of parameters,
but that would be a massive set. This branching approach should
be sufficient. It has fully replaced the previous set of
manually written test cases.

Bug: 150390069

Test: atest com.android.server.om.OverlayActorEnforcerTests
Test: atest OverlayRemountedTest

Change-Id: Iabf8b93307ee51ecced41335fdf47eb59c15c365