Skip filesystem verification if it's already done am: f844198240

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/2334902

Change-Id: Ica249f03837bd58e0de9d049eba621747436fe87
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>