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

test/cctest/wasm/test-run-wasm-module.cc

 // Copyright 2015 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.
 
 #include <stdlib.h>
 #include <string.h>
 
 #include "src/wasm/encoder.h"
 #include "src/wasm/wasm-js.h"
 #include "src/wasm/wasm-macro-gen.h"
@@ skipping 18 matching lines @@
   int32_t result =
       CompileAndRunWasmModule(isolate, module->Begin(), module->End());
   CHECK_EQ(expected_result, result);
 }
 }  // namespace
 
 
 // A raw test that skips the WasmModuleBuilder.
 TEST(Run_WasmModule_CallAdd_rev) {
   static const byte data[] = {
+      WASM_MODULE_HEADER,
       // sig#0 ------------------------------------------
       kDeclSignatures, 2, 0, kLocalI32,    // void -> int
       2, kLocalI32, kLocalI32, kLocalI32,  // int,int -> int
       // func#0 (main) ----------------------------------
       kDeclFunctions, 2, kDeclFunctionExport, 0, 0,  // sig index
       6, 0,                                          // body size
       kExprCallFunction, 1,                          // --
       kExprI8Const, 77,                              // --
       kExprI8Const, 22,                              // --
       // func#1 -----------------------------------------
@@ skipping 150 matching lines @@
   byte code2[] = {WASM_STORE_GLOBAL(global1, WASM_I32(56)),
                   WASM_STORE_GLOBAL(global2, WASM_I32(41)),
                   WASM_RETURN(WASM_CALL_FUNCTION0(f1_index))};
   f->EmitCode(code2, sizeof(code2));
   WasmModuleWriter* writer = builder->Build(&zone);
   TestModule(writer->WriteTo(&zone), 97);
 }
 #endif
 
 #endif  // !V8_TARGET_ARCH_ARM64