[wasm] Implement correct 2-level namespace for imports.

test/mjsunit/wasm/start-function.js

 // 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: --expose-wasm
 
 load("test/mjsunit/wasm/wasm-constants.js");
 load("test/mjsunit/wasm/wasm-module-builder.js");
 
 function instantiate(sig, body) {
@@ skipping 81 matching lines @@
 
   var module = builder.instantiate();
   var memory = module.exports.memory.buffer;
   var view = new Int8Array(memory);
   assertEquals(77, view[0]);
 })();
 
 (function testStartFFI() {
   print("testStartFFI");
   var ranned = false;
-  var ffi = { foo : function() {
+  var ffi = {gak: {foo : function() {
     print("we ranned at stert!");
     ranned = true;
-  }};
+  }}};
 
   var builder = new WasmModuleBuilder();
   var sig_index = builder.addType(kSig_v_v);
 
-  builder.addImport("foo", sig_index);
+  builder.addImport("gak", "foo", sig_index);
   var func = builder.addFunction("", sig_index)
     .addBody([kExprCallFunction, 0]);
 
   builder.addStart(func.index);
 
   var module = builder.instantiate(ffi);
   assertTrue(ranned);
 })();