Bug#973287: systemd autopkgtest-virt-lxc failure on arm64

[Ryutaroh Matsumoto]

>> > We probably need to cherry-pick two changes
> I released 246.6-5 with those changes the other day.

I run autopkgtest 246.6-5 on amd64 and arm64 VM.
"upstream" sometimes succeeds and sometimes fails, so I assume it
is OK.

"storage" consistently fails on arm64 VM. The reason is simple as below:
modprobe: FATAL: Module scsi_debug not found in directory /lib/modules/5.9.0-3-arm64

linux-image-arm64 does not have scsi_debug kernel module.
I have no idea which package is responsible for autopkgtest error of "storage".

By the way, systemd autopkgtest-virt-qemu works fine if packages with
"Priority: important" are included in VM.
But packages "Priority: required" is only included, the systemd test script fails.
Is it considered as a bug??

Coverage of packages in VM can be adjusted by
https://github.com/emojifreak/qemu-arm-image-builder/blob/main/build-gpt-autopkgtest-qemu-debian.sh

Best regards, Ryutaroh