Remove runtime flags for sloppy mode block scoping features

test/mjsunit/es6/spread-call-super-property.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-sloppy
-
 (function testCallSuperPropertyStrict() {
   "use strict";
   class BaseClass {
     method(...args) { return [this].concat(args); }
   }
   class SubClass extends BaseClass {
     method(...args) { return super.method(...args); }
   }
 
   var c = new SubClass();
   assertEquals([c, 1, 2, 3, 4, 5], c.method(1, 2, 3, 4, 5));
 })();
 
 
 (function testCallSuperPropertySloppy() {
   class BaseClass {
     method(...args) { return [this].concat(args); }
   }
   class SubClass extends BaseClass {
     method(...args) { return super.method(...args); }
   }
 
   var c = new SubClass();
   assertEquals([c, 1, 2, 3, 4, 5], c.method(1, 2, 3, 4, 5));
 })();