Provide way for --shell-after to also run after restore

Currently if you want to debug something happening in the restore section for a task, there doesn't seem to be a supported way to get a shell after the task has been restored. What I've taken to doing is putting the snippet from the restore section I want to test at the end of the execute section and using `--shell-after`. It would be nice if there was a `--shell-final` or something which just runs through everything and then drops you to a shell to inspect if your restore snippet worked as expected.