UPSTREAM: erofs-utils: lib: treat data blocks filled with 0s as a hole am: 90c7f666d9

Original change: https://android-review.googlesource.com/c/platform/external/erofs-utils/+/3117095

Change-Id: I8b947d4afa98ddf97d88334ea2917d45f0faa763
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>