VariableLengthVector Allocation Policy: Never reallocate memory. This policy, when used from
VariableLengthVector::SetSize(), always implies that the previous internal buffer will be kept. Even if not enough memory was available.
The typical use case of this policy is to make sure a
VariableLengthVector is not a proxy object.
oldSize == newSize, checked by assertion
|bool||operator() (unsigned int newSize, unsigned int oldSize) const|