Make nodeList schedulable

The conformance test "validates resource limits of pods that are
allowed to run" is failed if master node doesn't have taints.
The reason is that nodeList which should consist of schedulable
nodes is gotten with GetMasterAndWorkerNodes() and master nodes
were excluded from nodeList.
This makes nodeList be gotten with GetReadySchedulableNodesOrDie()
and nodeList can consist of schedulable nodes.

Author: Kenichi Omichi

test/e2e/scheduling/predicates.go

@@ -87,10 +87,17 @@ var _ = SIGDescribe("SchedulerPredicates [Serial]", func() {
 		var err error
 
 		framework.AllNodesReady(cs, time.Minute)
-		masterNodes, nodeList, err = e2enode.GetMasterAndWorkerNodes(cs)
+
+		// NOTE: Here doesn't get nodeList for supporting a master nodes which can host workload pods.
+		masterNodes, _, err = e2enode.GetMasterAndWorkerNodes(cs)
 		if err != nil {
 			e2elog.Logf("Unexpected error occurred: %v", err)
 		}
+		nodeList, err = e2enode.GetReadySchedulableNodesOrDie(cs)
+		if err != nil {
+			e2elog.Logf("Unexpected error occurred: %v", err)
+		}
+
 		// TODO: write a wrapper for ExpectNoErrorWithOffset()
 		framework.ExpectNoErrorWithOffset(0, err)