[modules] Implement namespace imports.

test/mjsunit/modules-skip-namespace.js

Index: test/mjsunit/modules-skip-namespace.js
diff --git a/test/mjsunit/modules-skip-namespace.js b/test/mjsunit/modules-skip-namespace.js
new file mode 100644
index 0000000000000000000000000000000000000000..ff6a7b81d3b03efd09325fe3bef8a9d7f42b6ffd
--- /dev/null
+++ b/test/mjsunit/modules-skip-namespace.js
@@ -0,0 +1,13 @@
+// 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.
+
+//assertEquals(
+//    ["ns", Symbol.toStringTag, Symbol.iterator], Reflect.ownKeys(ns2));
+//assertEquals(["ns"], [...ns2]);
+
+export * from "modules-skip-4.js";
+export * from "modules-skip-5.js";
+export var zzz = 123;
+export {ns2};
+import * as ns2 from "modules-namespace2.js";