`tools/destroy_virtual_hardware.sh` is missing some new steps

I have an "uninstall the control plane and reinstall it with whatever is in ~/git/omicron" shell script. It is not very good but it reliably keeps me from forgetting a step when I need to set up a control plane. One thing the script does is always run pfexec ./tools/destroy_virtual_hardware.sh after omicron-package uninstall, because external networking does not appear to function for me if I don't destroy and re-create the switch zone. (This is perhaps another issue; should I not need to have to do this?)

Two recent changes have resulted in me making changes to my script that destroy_virtual_hardware.sh doesn't know about:

• #3571: The sled agent now configures a swap device. I need to identify which device was added as swap and pfexec swap -d it.
• #4212: The sled agent now disables fmd, mounts a new dataset to /var/fm/fmd, and enables fmd again. I need to do the inverse (disable fmd, unmount, enable fmd) to undo that.

I think something should be doing this cleanup but I'm not sure what.

Start with tools/destroy_virtual_hardware.sh and compare its cleanup steps with the changes described in #3571 and #4212. Identify how the swap device and fmd dataset are handled by the sled agent, then update the destruction flow so those resources are reversed reliably. Done means the script cleans up both additions without requiring manual steps.