This commit fixes the original #11027 fix, which assumed that the
hyper-v provider just wasn't properly getting a VM id when it listed
snapshots. In reality, it was just that if you invoke the
`with_target_vm` method with no arguments, it runs on the entire environment.
This meant that the capability snapshot_list attempted to be invoked on
machines that didn't exist yet, which is the original cause for why the
list_snapshot method did not recieve a vm ID. This commit fixes that by
simply skipping the machine if it does not yet exist.
f998e535ce