Only promote remote animator to top sched group during animation

When running remote animation or SystemUI has requested top
priority (for example. when notifacition shade is open on top of
application), make sure to let it have exclusive top sched group
access. This reduces contention between app and entity running
remote animation as remote animator process gets exclusive access
to certain CPUs.

Test: Manual inspection of trace
Test: asit/perf/appstartup_non_hermetic_cyclic_dropcache_test
Bug: 157407136
Change-Id: I1bc495a1c536656f277a8e4aefc72f88d596c97a