[modules] Add tests for empty imports.

test/mjsunit/modules-empty-import4.js

Index: test/mjsunit/modules-empty-import4.js
diff --git a/test/mjsunit/modules-empty-import4.js b/test/mjsunit/modules-empty-import4.js
new file mode 100644
index 0000000000000000000000000000000000000000..0cea643414824036ba4d19feaef199f8b7d7c0a8
--- /dev/null
+++ b/test/mjsunit/modules-empty-import4.js
@@ -0,0 +1,11 @@
+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// MODULE
+
+import "modules-skip-empty-import.js";
+import {} from "modules-skip-empty-import.js";
+export {} from "modules-skip-empty-import.js";
+import {counter} from "modules-skip-empty-import-aux.js";
+assertEquals(1, counter);