[wasm][asm.js] Fix and enable several asm.js tests with the new parser.

test/mjsunit/asm/regress-681707.js

 // Copyright 2017 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: --validate-asm
+// Flags: --validate-asm --fast-validate-asm
 
 var foo = (function(stdlib) {
   "use asm";
   var bar = (stdlib[0]);
   function foo() { return bar ("lala"); }
   return foo;
 })(this);
 
 try {
   nop(foo);
   foo();
 } catch (e) {
 }