filterOutSchedulableByPacking is an alternative to the older
filterOutSchedulable. filterOutSchedulableByPacking sorts pods in
unschedulableCandidates by priority and filters out pods that can be
scheduled on free capacity on existing nodes. It uses a basic packing
approach to do this. Pods with nominatedNodeName set are always
filtered out.
filterOutSchedulableByPacking is set to be used by default, but, this
can be toggled off by setting filter-out-schedulable-pods-uses-packing
flag to false, which would then activate the older and more lenient
filterOutSchedulable(now called filterOutSchedulableSimple).
Added test cases for both methods.