Merge "libprocessgroup: UIDs in linux are unsigned" into main am: a414e2fd9b am: 6094c610ad

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

Change-Id: Ie5ffd7da135c270a8ed437d23e3751b8ecbe1ce7
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>