Shared: Do not use @kind graph for CFG test output

Author: hvitved

csharp/ql/test/library-tests/controlflow/graph/NodeGraph.expected

@@ -1,12 +1,3 @@
-/**
- * @kind graph
- */
-
 import csharp
 import Common
-
-private class MyRelevantNode extends SourceControlFlowNode {
-  string getOrderDisambiguation() { result = "" }
-}
-
-import semmle.code.csharp.controlflow.internal.ControlFlowGraphImpl::TestOutput<MyRelevantNode>
+import semmle.code.csharp.controlflow.internal.ControlFlowGraphImpl::TestOutput<SourceControlFlowNode>