Add CTS tests for SELinux related change ids

Test that SELINUX_R_CHANGES and SELINUX_LATEST_CHANGES place an app in
the appropriate selinux domain. The R domain is currently the latest, so
test will need to be updated once that changes.

These tests are a more end-to-end variant of com.android.server.pm.SELinuxMMACTest.

Test: atest CompatChangesSelinuxTest
Bug: 168782947
Change-Id: I6f9ddce61d95f40687d9d8fa1ac87e95e72c38e1