[TEST] Ensure creation of valid routing table

An additional sanity check introduced by #17821 makes some tests fail. This check verifies that
only one shard with same shard id is allocated to a node. This commit fixes a bug in
ClusterStateCreationUtils which would construct a cluster state that allocated two shards with same
id to the same node.

core/src/test/java/org/elasticsearch/action/support/replication/ClusterStateCreationUtils.java

@@ -107,6 +107,7 @@ public class ClusterStateCreationUtils {
                 Set<String> unassignedNodesExecludingPrimary = new HashSet<>(unassignedNodes);
                 unassignedNodesExecludingPrimary.remove(newNode(0).getId());
                 primaryNode = selectAndRemove(unassignedNodesExecludingPrimary);
+                unassignedNodes.remove(primaryNode);
             }
             if (primaryState == ShardRoutingState.RELOCATING) {
                 relocatingNode = selectAndRemove(unassignedNodes);