Description of problem:
When creating a VM with instance type with memory hugepages defined, the validation check relies on spec.template.spec.domain.resources being populated with resource requests, something that isn't ensured until the VirtualMachineInstance mutation webhook runs later when launching the VM


Version-Release number of selected component (if applicable):
4.13

How reproducible:
100%

Steps to Reproduce:
1. Create a VM InstanceType with hugepages
2. Create a VM with the InstanceType reference
3. Start the VM

Actual results:
The VM gives an Error:
{
"reason":"FieldValueInvalid",
"message":"spec.template.spec.domain.resources.requests.memory \\'0\\' must be equal to or larger than page size spec.template.spec.domain.hugepages.size \\'1Gi\\'",
"field":"spec.template.spec.domain.resources.requests.memory"
}

Expected results:
VM would start

Additional info:
An upstream bug/PR attached in links