Also check new_target_is_base() bit when comparing two maps for equivalence.

BUG=chromium:580506
LOG=N

Review URL: https://codereview.chromium.org/1631673002

Cr-Commit-Position: refs/heads/master@{#33497}

src/objects.cc

@@ -12250,6 +12250,7 @@ bool CheckEquivalent(Map* first, Map* second) {
          first->bit_field() == second->bit_field() &&
          first->is_extensible() == second->is_extensible() &&
          first->is_strong() == second->is_strong() &&
+         first->new_target_is_base() == second->new_target_is_base() &&
          first->is_hidden_prototype() == second->is_hidden_prototype();
 }
 

test/mjsunit/mjsunit.status

@@ -1034,6 +1034,7 @@
   'regress/regress-crbug-572590': [SKIP],
   'regress/regress-crbug-573857': [SKIP],
   'regress/regress-crbug-575080': [SKIP],
+  'regress/regress-crbug-580506': [SKIP],
   'regress/regress-deopt-gcb': [SKIP],
   'regress/regress-deopt-gc': [SKIP],
   'regress/regress-deopt-in-array-literal-spread': [SKIP],

test/mjsunit/regress/regress-crbug-580506.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: --allow-natives-syntax
+
+(function() {
+  'use strict';
+  class A extends Function {
+    constructor(...args) {
+      super(...args);
+      this.a = 42;
+    }
+  }
+  var v1 = new A("'use strict';");
+  function f(func) {
+    func.__defineSetter__('a', function() { });
+  }
+  var v2 = new A();
+  f(v2);
+  f(v1);
+})();