Remove destructuring and default arguments runtime flags

test/mjsunit/es6/destructuring-assignment.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: --harmony-destructuring-assignment --harmony-destructuring-bind
-
 // script-level tests
 var ox, oy = {}, oz;
 ({
   x: ox,
   y: oy.value,
   y2: oy["value2"],
   z: ({ set v(val) { oz = val; } }).v
 } = {
   x: "value of x",
   y: "value of y1",
@@ skipping 456 matching lines @@
       assertEquals(["s", "p", "o", "r", "k"], x.rest);
       break;
     }
     log.push({ firstLetter: x.firstLetter, rest: x.rest });
   }
   assertEquals([
     { firstLetter: "\u{1F382}", rest: ["c", "a", "k", "e"] },
     { firstLetter: "B", rest: ["p", "u", "p", "p", "y"] },
   ], log);
 })();