Add progress updates to FilesystemVerificationAction am: 70eef23d3a am: 1f75fdc9fb am: 4bd35dc048 am: fbe483a846 am: 6414e731d4

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

Change-Id: Ia095be3b8a5e10a2529a5ebaacfb91cde1749533