Merge "Nullability check for pidfd module" am: 7f8133dc2f

Original change: https://android-review.googlesource.com/c/platform/bionic/+/2478476

Change-Id: I5145cb5986ae49e330e9b83fe93500561d8c6ab4
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>