Merge "libprocessgroup: return false on failure" am: 64f953e2 am: b3e5d4ed am: f3dcab61

Original change: https://android-review.googlesource.com/c/platform/system/core/+/2059547



Change-Id: I2e31451352e1b9e26f3c303765e60870590bc350
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>