Merge "Nullability check for thread module" am: dddea28a74

Original change: https://android-review.googlesource.com/c/platform/bionic/+/2480425

Change-Id: If52bf6bab08bf7d692c693d7285fba4eefa1f926
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>