JS: Add test showing missing re-export of base class relationship

javascript/ql/test/library-tests/ModelGeneration/ModelGeneration.expected

@@ -45,6 +45,9 @@ typeModel
 | (subclass).C | subclass | Member[C] |
 | (subclass).C.prototype | (subclass).C | Instance |
 | (subclass).C.prototype.c | (subclass).C.prototype | Member[c] |
+| (subclass).D | subclass | Member[D] |
+| (subclass).D.prototype | (subclass).D | Instance |
+| (subclass).D.prototype.d | (subclass).D.prototype | Member[d] |
 | upstream-lib | (reexport).func | ReturnValue |
 | upstream-lib | reexport | Member[lib] |
 | upstream-lib.XYZ | reexport | Member[x].Member[y].Member[z] |

javascript/ql/test/library-tests/ModelGeneration/ModelGeneration.ext.yml

@@ -4,3 +4,4 @@ extensions:
       extensible: typeModel
     data:
       - ["upstream-lib.XYZ", "upstream-lib", "Member[x].Member[y].Member[z]"]
+      - ["upstream-lib.Type", "upstream-lib", "Member[Type].Instance"]

javascript/ql/test/library-tests/ModelGeneration/subclass/subclass.js

@@ -9,3 +9,11 @@ export class B extends A {
 export class C extends B {
     c() {}
 }
+
+import * as upstream from "upstream-lib";
+
+// TODO: needs to emit type model: [upstream.Type; (subclass).D.prototype; ""]
+// The getAValueReachableFromSource() logic does not handle the base class -> instance step
+export class D extends upstream.Type {
+    d() {}
+}