Merge "Nullability check for execinfo module" am: e87938c435 am: ead933d373

Original change: https://android-review.googlesource.com/c/platform/bionic/+/2386455

Change-Id: Ic32de01f76b4439e18389f8abd822c09ffb5c683
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>