Merge "Nullability check for xattr module." am: 0f371ff845

Original change: https://android-review.googlesource.com/c/platform/bionic/+/2597870

Change-Id: Ic72d94527f22504e6e43644756999a93aff39af9
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>