JS: Add test showing FN source

javascript/ql/test/library-tests/frameworks/HTTP/RemoteRequestInput.expected

@@ -1,5 +1,6 @@
 | connect.js:6:5:6:11 | req.url | url |
 | connect.js:7:5:7:21 | req.cookies.get() | cookie |
+| express-typed.ts:4:5:4:12 | req.body | body |
 | express.js:12:5:12:19 | req.param("p1") | parameter |
 | express.js:13:5:13:17 | req.params.p2 | parameter |
 | express.js:14:5:14:16 | req.query.p3 | parameter |

javascript/ql/test/library-tests/frameworks/HTTP/express-typed.ts

@@ -0,0 +1,11 @@
+import { Request } from "express";
+
+export function f1(req: Request) {
+    req.body;
+}
+
+type Alias = Request & { foo: string };
+
+export function f2(req: Alias) {
+    req.body;
+}