Fix eval calls in initializers of arrow function parameters

test/mjsunit/harmony/regress/regress-4395.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 --harmony-default-parameters
 
 (function testExpressionTypes() {
   "use strict";
   ((x, y = x) => assertEquals(42, y))(42);
 
@@ skipping 78 matching lines @@
   }
 
   class D extends C{
     constructor() {
       ((q = super()) => assertEquals(42, q.prop))();
     }
   }
 
   new D();
 })();
+
+
+(function testScopeFlags() {
+  ((x, y = eval('x')) => assertEquals(42, y))(42);
+})();