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

test/mjsunit/wasm/divrem-trap.js

Index: test/mjsunit/wasm/divrem-trap.js
diff --git a/test/mjsunit/wasm/divrem-trap.js b/test/mjsunit/wasm/divrem-trap.js
index 9787ae34c9d5dca2b87643f47fdae9f6b7f54ac6..08d1cd82a988e122510d2b748df0b989c1ba6bb2 100644
--- a/test/mjsunit/wasm/divrem-trap.js
+++ b/test/mjsunit/wasm/divrem-trap.js
@@ -31,9 +31,9 @@ function assertTraps(code, msg) {
 
 function makeDivRem(opcode) {
   var kBodySize = 5;
-  var kNameMainOffset = 6 + 11 + kBodySize + 1;
+  var kNameMainOffset = kHeaderSize + 6 + 11 + kBodySize + 1;
 
-  var data = bytes(
+  var data = bytesWithHeader(
     // signatures
     kDeclSignatures, 1,
     2, kAstI32, kAstI32, kAstI32, // (int,int) -> int