node_tests: Move to web/tests.

This lets us simplify the long-ish ‘../../static/js’ paths, and will
remove the need for the ‘zrequire’ wrapper.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

web/tests/lib/real_jquery.js

@@ -0,0 +1,8 @@
+"use strict";
+
+const jquery = require("jquery");
+
+// so the tests can mock jQuery
+delete require.cache[require.resolve("jquery")];
+
+module.exports = jquery;