Support squashfs in map_file_generator am: df9821b893

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/2620039

Change-Id: Id7179416fb5deaa6a8f7157e35be4649e712b32c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>