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: Ib5df2633ee0db37a6711fd5addaa26674596e3c5
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>