Merge "libprocessgroup: Check validity of uid and pid arguments" am:...

Merge "libprocessgroup: Check validity of uid and pid arguments" am: c1798def am: f5d65bf1 am: 92824d9d am: 9cff1345

Original change: https://android-review.googlesource.com/c/platform/system/core/+/2475605



Change-Id: I561c3889f72435d76108d2c66fd8148f704933d3
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>