Remove all harmony runtime flags which shipped in M51

test/mjsunit/es6/unicode-escapes-in-regexps.js

 // Copyright 2014 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.
 
 // ES6 extends the \uxxxx escape and also allows \u{xxxxx}.
 
-// Flags: --harmony-unicode-regexps
-
 function testRegexpHelper(r) {
   assertTrue(r.test("foo"));
   assertTrue(r.test("boo"));
   assertFalse(r.test("moo"));
 }
 
 
 (function TestUnicodeEscapes() {
   testRegexpHelper(/(\u0066|\u0062)oo/);
   testRegexpHelper(/(\u0066|\u0062)oo/u);
@@ skipping 259 matching lines @@
 assertNull(new RegExp("\ud800\\udc00+", "u").exec("\u{10000}\u{10000}"));
 
 assertNull(new RegExp("[\\ud800\udc00]", "u").exec("\u{10000}"));
 assertNull(new RegExp("[\\{ud800}\udc00]", "u").exec("\u{10000}"));
 assertNull(new RegExp("[\ud800\\udc00]", "u").exec("\u{10000}"));
 assertNull(new RegExp("[\ud800\\{udc00}]", "u").exec("\u{10000}"));
 
 assertNull(/\u{d800}\u{dc00}+/u.exec("\ud800\udc00\udc00"));
 assertNull(/\ud800\u{dc00}+/u.exec("\ud800\udc00\udc00"));
 assertNull(/\u{d800}\udc00+/u.exec("\ud800\udc00\udc00"));