JS: Add CG test showing lack of calls down to subclasses

javascript/ql/test/library-tests/CallGraphs/AnnotatedTest/subclasses.js

@@ -0,0 +1,37 @@
+import 'dummy';
+
+class Base {
+    workInBase() {
+        /** calls:methodInBase */
+        this.methodInBase();
+
+        /** calls:NONE */
+        this.methodInSub();
+    }
+
+    /** name:methodInBase */
+    methodInBase() {
+        /** calls:NONE */
+        this.methodInSub();
+    }
+}
+
+class Subclass1 extends Base {
+    workInSub() {
+        /** calls:methodInBase */
+        this.methodInBase();
+    }
+
+    methodInSub() {
+    }
+}
+
+class Subclass2 extends Base {
+    workInSub() {
+        /** calls:methodInBase */
+        this.methodInBase();
+    }
+
+    methodInSub() {
+    }
+}