Upgrade Wasm JS API, step 1

test/mjsunit/wasm/wasm-module-builder.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.
 
 function WasmFunctionBuilder(name, sig_index) {
     this.name = name;
     this.sig_index = sig_index;
     this.exports = [];
 }
 
@@ skipping 324 matching lines @@
     var buffer = new ArrayBuffer(bytes.length);
     var view = new Uint8Array(buffer);
     for (var i = 0; i < bytes.length; i++) {
         var val = bytes[i];
         if ((typeof val) == "string") val = val.charCodeAt(0);
         view[i] = val | 0;
     }
     return buffer;
 }
 
-WasmModuleBuilder.prototype.instantiate = function(ffi, memory) {
-    var buffer = this.toBuffer();
-    if (memory != undefined) {
-      return Wasm.instantiateModule(buffer, ffi, memory);
-    } else {
-      return Wasm.instantiateModule(buffer, ffi);
-    }
+WasmModuleBuilder.prototype.instantiate = function(...args) {
+  var module = new WebAssembly.Module(this.toBuffer());
+  var instance = new WebAssembly.Instance(module, ...args);
+  return instance;
 }