Use ASSERT_* instead of EXPECT_* to abort test early am: e53a318729

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/2803168

Change-Id: Ia5f5721f84a14a214ec5d72cea1568b9a6c52b45
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>