Symptom: Force gc caused activity launch time took longer
Root Cause: Runtime.getRuntime().gc will block binder thread
Solution: Use VMRuntime.requestConcurrentGC() will not block binder
thread
(cherry pick commit d916c233f0)
Bug: 20554807
Change-Id: Ia9fecea51d2b0a6635e037b5f2bfcb8eb87f4103