Make system server profiling an explicit runtime intent

Pass an explicit flag to the runtime when we need to profile the system
server. This ensures that we only start the ProfileSaver and allocate the
code cache when needed.

Test: manual, on a device with system server profiling enabled
Bug: 74081010

(cherry picked from commit 8eb891be)

Merged-In: I756682a9644796afb53f0c010d2bd2764ea5a828
Change-Id: I756682a9644796afb53f0c010d2bd2764ea5a828