Fix errorprone warnings that should be errors am: 6aa0b94839

Original change: https://android-review.googlesource.com/c/platform/test/mlts/benchmark/+/2254751

Change-Id: I02da0b9531d3a3487e451067c5e027e32637897a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>