Add --enable-wasm to wasm tests.

test/mjsunit/wasm/ffi.js

 // 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.
 
+// Flags: --expose-wasm
+
 load("test/mjsunit/wasm/wasm-constants.js");
 
 function testCallFFI(func, check) {
   var kBodySize = 6;
   var kNameFunOffset = 24 + kBodySize + 1;
   var kNameMainOffset = kNameFunOffset + 4;
 
   var ffi = new Object();
   ffi.fun = func;
 
@@ skipping 307 matching lines @@
 
   assertEquals("function", typeof module.main);
 
   for (var i = -9; i < 900; i += 6.125) {
       module.main(i);
   }
 }
 
 testCallPrint();
 testCallPrint();