[wasm] Compile closer to how customers will.

third_party/WebKit/LayoutTests/http/tests/wasm/resources/load_wasm.js

 // Copyright 2016 The Chromium 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 createWasmModule() {
     // the file incrementer.wasm is copied from
     // //v8/test/mjsunit/wasm. This is because currently we cannot
     // reference files outside the LayoutTests folder. When wasm format
     // changes require that file to be updated, there is a test on the
     // v8 side (same folder), ensure-wasm-binaries-up-to-date.js, which
     // fails and will require incrementer.wasm to be updated on that side.
     return fetch('incrementer.wasm')
         .then(response => {
             if (!response.ok) throw new Error(response.statusText);
             return response.arrayBuffer();
         })
-        .then(data => {
-            var mod = new WebAssembly.Module(data);
-            return mod;
-        });
+        .then(WebAssembly.compile);
 }