Its omission was meant to be an error and as far as I'm aware it was meant to be restored in a future update, since we have had two program updates since then I'm surprised it isn't back.
For now it is a workaround to disable it in the registry.
- Avast & Intel Virtualisation - disable avast hardware virtualisation, see:
I see it was removed unintentionally 
-- as a workaround, you can disable 'self protection' (in troubleshooting), run regedit.exe and set Start=4 in HKEY_LOCAL_MACHINE\System\CurrentControlSet\services\aswvmm.
That said you have to be comfortable and careful working in the registry.
