Merge "libprocessgroup: UIDs in linux are unsigned" into main am: a414e2fd9b

Original change: https://android-review.googlesource.com/c/platform/system/core/+/2670104

Change-Id: I6e204bdaf1120e81aaae9d52736f5a86df522763
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>