Auto-grant permission to root/system/self

Ensure that root gets all permissions for some native tests that still run as root.

Fast-path self/root/system-uid checks, since they should get all permission from our perspective.

Test: atest audiosystem_tests
Bug: 353253918
Bug: 338089555
Flag: com.android.media.audio.audioserver_permissions
Change-Id: I478fb7dcf031f10f4657a7909e2446f530c0549b