Merge "Nullability check for system_properties module." am: 83f9b28792 am: 4eccad6838 am: c03f1a706d am: 4d0186ac4e

Original change: https://android-review.googlesource.com/c/platform/bionic/+/2593054

Change-Id: Ic717c90de68915d9fb4c990632ec252d53bdcdce
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>