[serializer] do not serialize script wrappers.

test/mjsunit/regress/wasm/regression-674447.js

Index: test/mjsunit/regress/wasm/regression-674447.js
diff --git a/test/mjsunit/regress/wasm/regression-674447.js b/test/mjsunit/regress/wasm/regression-674447.js
new file mode 100644
index 0000000000000000000000000000000000000000..228b038334b79109d0f523ed917315ced7355464
--- /dev/null
+++ b/test/mjsunit/regress/wasm/regression-674447.js
@@ -0,0 +1,10 @@
+// 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.
+
+// Flags: --validate-asm --cache=code
+
+(function() {
+  "use asm";
+  return function f() {}
+})();