Add progress updates to FilesystemVerificationAction am: 70eef23d3a am: 1f75fdc9fb am: 4bd35dc048 am: fbe483a846

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/1334015

Change-Id: Ifd4a8bb3ce60be6a67bc6ba806d1db07b277bf36