cow estimator: terminate on bad write am: 0b735f6cd2

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/3026185

Change-Id: I94570af35827f9eac9e59103623c0b83316070f8
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>