[regexp, intl] Intl should not cause side effects to the RegExp object.

test/intl/regexp-assert.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.
+
+assertEquals("", RegExp.$1);
+assertEquals("", RegExp.$2);
+assertEquals("", RegExp.$3);
+assertEquals("", RegExp.$4);
+assertEquals("", RegExp.$5);
+assertEquals("", RegExp.$6);
+assertEquals("", RegExp.$7);
+assertEquals("", RegExp.$8);
+assertEquals("", RegExp.$9);
+
+assertEquals("", RegExp.lastMatch);
+assertEquals("", RegExp.lastParen);
+assertEquals("", RegExp.leftContext);
+assertEquals("", RegExp.rightContext);
+assertEquals("", RegExp.input);