cpuset: Make 'ToSlice*' methods look like 'set' methods

In 'set', conversions to slice are done also, but with different names:

ToSliceNoSort() -> UnsortedList()
ToSlice() -> List()

Reimplement List() in terms of UnsortedList to save some duplication.

test/e2e_node/memory_manager_test.go

@@ -280,7 +280,7 @@ var _ = SIGDescribe("Memory Manager [Disruptive] [Serial] [Feature:MemoryManager
 		currentNUMANodeIDs, err := cpuset.Parse(strings.Trim(output, "\n"))
 		framework.ExpectNoError(err)
 
-		framework.ExpectEqual(numaNodeIDs, currentNUMANodeIDs.ToSlice())
+		framework.ExpectEqual(numaNodeIDs, currentNUMANodeIDs.List())
 	}
 
 	waitingForHugepages := func(ctx context.Context, hugepagesCount int) {