Add utility method to check payload's data hash am: b8d776c9b7 am: 97c47d4db8 am: b86b272840 am: 0029078a6a

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/2208897

Change-Id: I1bc3d2fc1cc42d0f562f2c2b0e76381845ad0d4b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>