Merge "Nullability check for sched module." am: 0fec9c0e19 am: 73a9885ec8

Original change: https://android-review.googlesource.com/c/platform/bionic/+/2496358

Change-Id: I602d506535d4af69b8ba69dc3706940212c30759
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>