Merge "Nullability check for execinfo module" am: e87938c435 am: ead933d373 am: 669a8732a4

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

Change-Id: I54ec29d9a6dd16fe7937f92d965f65a87ab5ff92
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>