NodeInfo.Allocatable.ScalarResources already knows which resources
are scaler. Also, if the resource name is not present,
it's pointless to compute score for a resources the node can not allocate
since nodeInfo.Allocatable.ScalarResources[resource] is zero for the case.
And both leastRequestedScore and mostRequestedScore returns 0 score
for nodes with zero allocatable resource.
The balancedResourceScorer deals only with CPU and memory which
are not scalable resources.
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