Import latest Ubuntu changes

This takes in a couple of recent packaging changes from Ubuntu. Basically tweaking the Ubuntu-specific AppArmor patching logic and disabling some tests which currently don't seem to work in autopkgtest.

Debian doesn't currently run those through autopkgtest but chances are that they'd fail in the same way, so I think it makes sense to take the change. As mentioned in the commit message, those tests are run upstream, so it's really an environment failure that needs to be sorted out.