Merge "Nullability check for shm module." am: 374d2f1be0

Original change: https://android-review.googlesource.com/c/platform/bionic/+/2601525

Change-Id: I775dfbee4770b643c90c75c3f40d077a58d013ee
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>