Merge "Nullability check for time module." am: b167b90b4c

Original change: https://android-review.googlesource.com/c/platform/bionic/+/2580375

Change-Id: Ifb3f7c83e53ffb5c7008d14d0256368fe5c3a469
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>