Merge "Nullability check for mman module." am: b72900c5c9 am: ebd33d5977 am: c5ce34172c am: c2520bbdeb

Original change: https://android-review.googlesource.com/c/platform/bionic/+/2580311

Change-Id: Ida336471893c84cb292a2ffd7ee9020141fbf31b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>