[wasm] asm.js - Remove Wasm.instantiateModuleFromAsm, use asm.js directly.

test/mjsunit/regress/regress-613928.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: --expose-wasm
+// Flags: --validate-asm --allow-natives-syntax
 
 (function __f_54() {
   function __f_41(stdlib, __v_35) {
     "use asm";
     __v_35 = __v_35;
     function __f_21(int_val, double_val) {
       int_val = int_val|0;
       double_val = +double_val;
     }
     return {__f_21:__f_21};
   }
-  assertThrows(function() {Wasm.instantiateModuleFromAsm(__f_41.toString())});
+  __f_41();
+  assertTrue(%IsNotAsmWasmCode(__f_41));
 })();