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

test/mjsunit/wasm/asm-wasm-stdlib.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: --validate-asm --allow-natives-syntax
+// Flags: --validate-asm --allow-natives-syntax --fast-validate-asm
 
 var stdlib = this;
 
 function assertValidAsm(func) {
   assertTrue(%IsAsmWasmCode(func));
 }
 
 (function TestStdlibConstants() {
   function Module(stdlib) {
     "use asm";
@@ skipping 435 matching lines @@
           if (!compare(expected, actual)) {
             print(expected + ' !== ' + actual + ' for ' + name +
                   ' with input ' + val0 + ' ' + val1);
             assertTrue(false);
           }
         }
       }
     }
   }
 })();