Merge "libsnapshot_cow: Prepare device to boot from pre-created snapshots" into main am: 6b78aac2cf

Original change: https://android-review.googlesource.com/c/platform/system/core/+/2746258

Change-Id: Ifd60bf5bd01084a28a47244fefdf7867a62ac10c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>