querying smbios type=1 UUID in Windows not possible when using SMBIOS 64 bit entry
Description of problem:
Querying the UUID in Powershell with
`get-wmiobject win32_computersystemproduct | Select-Object -expandProperty UUID`
will return no value. When using `-machine 'pc-i440fx-8.1,smbios-entry-point-type=32'` or `-machine 'pc-i440fx-8.0'` the command works as expected. When using `-machine 'pc-i440fx-8.0,smbios-entry-point-type=64'` the issue is also present.

Commit bf376f3020dfd7bcb2c4158b4ffa85c04d44f56d changed the default for machine version 8.1, so that explains that part.

It's not clear to me if this is a bug in QEMU or a bug/limitation of the guest OS when 64 bit entry is used by SMBIOS.
Additional information:
Originally reported for Windows 10 in the Proxmox VE community forum (AFAIK the downstream build in Proxmox VE does not patch the relevant code paths):
https://forum.proxmox.com/threads/136942/