[regexp] Set static property attributes as in spec proposal

test/mjsunit/regress/regress-5566.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.
+
+// https://github.com/tc39/proposal-regexp-legacy-features#additional-properties-of-the-regexp-constructor
+
+const re = /./;
+
+re.exec("abc");
+
+const props = [ "input", "$_"
+              , "lastMatch", "$&"
+              , "lastParen", "$+"
+              , "leftContext", "$`"
+              , "rightContext", "$'"
+              , "$1", "$2", "$3", "$4", "$5", "$6", "$7", "$8", "$9"
+              ];
+
+for (let i = 0; i < props.length; i++) {
+  const prop = props[i];
+  assertTrue(Object.getOwnPropertyDescriptor(RegExp, prop).configurable, prop);
+  assertFalse(Object.getOwnPropertyDescriptor(RegExp, prop).enumerable, prop);

[Dan Ehrenberg, 2016/10/26 08:36:41]

While you're looking at the property descriptors, it'd be nice to check that
these are getter/setters.

[jgruber, 2016/10/26 09:30:43]

Done, and also changed setters to be undefined instead of the EmptyFunction
builtin.

+}