Remove always-true --harmony-restrictive-declarations flag

test/mjsunit/regress/regress-536751.js

Index: test/mjsunit/regress/regress-536751.js
diff --git a/test/mjsunit/regress/regress-536751.js b/test/mjsunit/regress/regress-536751.js
deleted file mode 100644
index a63fae395722d072db82ce81f064a5f27705e5dd..0000000000000000000000000000000000000000
--- a/test/mjsunit/regress/regress-536751.js
+++ /dev/null
@@ -1,11 +0,0 @@
-// 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: --no-harmony-restrictive-declarations
-
-// At some point, this code led to DCHECK errors in debug mode
-
-for (; false;) function foo() {};
-
-for (x in []) function foo() {};