Merge "Don't write out cargo.out if it wasn't generated." into main am: 21592eede9 am: b131edfd41

Original change: https://android-review.googlesource.com/c/platform/development/+/3073727

Change-Id: I0ec212047181fb8b9bc0f440bc15cf5e0de73e2d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>