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

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

Change-Id: Id1cd27f8284d363639efa608e63cf4ba73c9f278
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>