Trigger GC Delay for subsequent launches.

Application launches for apps like GMS Music
and Maps lead to explicit GC's due to Binder
activity in the SystemServer. This change
allows delaying the GC for 3 seconds after
the application is launched. Subsequent launches
or first relaunches for killed applications
are also now covered.

Change-Id: I945f19b1363504f4d5f61deb1a3af23149b80e64