[wasm] Add a magic word and a version number to the binary.

test/mjsunit/wasm/stack.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");
 
 function testStack(func, check) {
   var kBodySize = 2;
-  var kNameFunOffset = 22 + kBodySize + 1;
+  var kNameFunOffset = kHeaderSize + 22 + kBodySize + 1;
   var kNameMainOffset = kNameFunOffset + 4;
 
   var ffi = new Object();
   ffi.fun = func;
 
-  var data = bytes(
+  var data = bytesWithHeader(
       // signatures
       kDeclSignatures, 1,  //  --
       0, kAstStmt,         // () -> void
       // -- foreign function
       kDeclFunctions, 2,                        //  --
       kDeclFunctionName | kDeclFunctionImport,  // --
       0, 0,                                     //  --
       kNameFunOffset, 0, 0, 0,                  // name offset
       // -- main function
       kDeclFunctionName | kDeclFunctionExport,  // --
@@ skipping 35 matching lines @@
     // The line numbers below will change as this test gains / loses lines..
     "    at STACK (stack.js:54:11)\n" +  // --
     "    at <WASM> (<anonymous>)\n" +  // --
     "    at <WASM> (<anonymous>)\n" +  // --
     "    at <WASM> (<anonymous>)\n" +  // --
     "    at testStack (stack.js:43:10)\n" +
     // TODO(jfb) Add WebAssembly stack here.
     "    at stack.js:72:1";
 
 testStack(STACK, check_STACK);