change indicator used for later versions of VirtualBox (#21127)

change indicator used for later versions of VirtualBox (#21127)

Detection of VirtualBox is accomplished in the existing code by *either* `innotek GmbH`
or `Oracle Corporation` existing in any of:

- /sys/class/dmi/id/product_name
- /sys/class/dmi/id/sys_vendor
- /sys/class/dmi/id/board_vendor
- /sys/class/dmi/id/bios_vendor

With Oracle's physical servers, both `/sys/class/dmi/id/sys_vendor` and
`/sys/class/dmi/id/board_vendor` contain `Oracle Corporation`, so those
servers are detected as `oracle` (VirtualBox).

VirtualBox has the following values in the latest versions:

- /sys/class/dmi/id/product_name: `VirtualBox`
- /sys/class/dmi/id/sys_vendor: `innotek GmbH`
- /sys/class/dmi/id/board_vendor: `Oracle Corporation`
- /sys/class/dmi/id/bios_vendor: `innotek GmbH`

Presumably the existing check for `innotek GmbH` is meant to detect
older versions of VirtualBox, while changing the second checked value
from `Oracle Corporation` to `VirtualBox` will reliably detect later and future
versions.