Support incremental OTA in ota_extractor am: 91e839cf19 am: fec3837e1b

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/2056749

Change-Id: Iad99f91d5077a5a7f7e209cfebf1512aa790647d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>