DO NOT MERGE: ActivityManager#killBackgroundProcesses can kill caller's own app only am: 8b382775

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/20309299



Change-Id: I501384d2eb14ab04fdca8c6638db7dba679e0e81
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>