Allow system server to record its own profile

On userdebug builds we can now profile system server without disabling
selinux. This is the final piece, and allows the system server to save its
own profile.

Test: manual, on a device with system server profiling enabled
Bug: 73313191
Change-Id: Iaf9575d3cda19ae4c38f1e20a8e1b9288b7abc83