[regexp] fix /\W/ui wrt \u017f and \u212a.

test/mjsunit/es7/regexp-ui-word.js

+// Copyright 2017 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.
+
+assertTrue(/\w/iu.test('\u017F'));
+assertTrue(/\w/iu.test('\u212A'));
+assertFalse(/\W/iu.test('\u017F'));
+assertFalse(/\W/iu.test('\u212A'));
+assertFalse(/\W/iu.test('s'));
+assertFalse(/\W/iu.test('S'));
+assertFalse(/\W/iu.test('K'));
+assertFalse(/\W/iu.test('k'));
+
+assertTrue(/[\w]/iu.test('\u017F'));
+assertTrue(/[\w]/iu.test('\u212A'));
+assertFalse(/[\W]/iu.test('\u017F'));
+assertFalse(/[\W]/iu.test('\u212A'));
+assertFalse(/[\W]/iu.test('s'));
+assertFalse(/[\W]/iu.test('S'));
+assertFalse(/[\W]/iu.test('K'));
+assertFalse(/[\W]/iu.test('k'));
+
+assertTrue(/\b/iu.test('\u017F'));
+assertTrue(/\b/iu.test('\u212A'));
+assertTrue(/\b/iu.test('s'));
+assertTrue(/\b/iu.test('S'));
+assertFalse(/\B/iu.test('\u017F'));
+assertFalse(/\B/iu.test('\u212A'));
+assertFalse(/\B/iu.test('s'));
+assertFalse(/\B/iu.test('S'));
+assertFalse(/\B/iu.test('K'));
+assertFalse(/\B/iu.test('k'));
+
+assertEquals(["abcd", "d"], /a.*?(.)\b/i.exec('abcd\u017F cd'));
+assertEquals(["abcd", "d"], /a.*?(.)\b/i.exec('abcd\u212A cd'));
+assertEquals(["abcd\u017F", "\u017F"], /a.*?(.)\b/iu.exec('abcd\u017F cd'));
+assertEquals(["abcd\u212A", "\u212A"], /a.*?(.)\b/iu.exec('abcd\u212A cd'));
+
+assertEquals(["a\u017F ", " "], /a.*?\B(.)/i.exec('a\u017F '));
+assertEquals(["a\u212A ", " "], /a.*?\B(.)/i.exec('a\u212A '));
+assertEquals(["a\u017F", "\u017F"], /a.*?\B(.)/iu.exec('a\u017F '));
+assertEquals(["a\u212A", "\u212A"], /a.*?\B(.)/iu.exec('a\u212A '));