Merge "ActivityManager: create process group in behalf of app zygote" into sc-dev am: 17893935 am: 7204ef6c

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/13562597

Change-Id: Ie339d7ec52a2f4327fc078c786f58e763a5a96ff