Revert "Remove U+180E from whitespace in js_runtime and tests"

tests/corelib_strong/int_parse_radix_test.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import "package:expect/expect.dart";
 import "dart:math" show pow;
 
 void main() {
   bool checkedMode = false;
   assert((checkedMode = true));
   const String oneByteWhiteSpace = "\x09\x0a\x0b\x0c\x0d\x20"
     "\x85"    /// 01: ok
     "\xa0";
-  const String whiteSpace = "$oneByteWhiteSpace\u1680"
+  const String whiteSpace = "$oneByteWhiteSpace\u1680\u180e"
       "\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a"
       "\u2028\u2029\u202f\u205f\u3000\ufeff";
 
   var digits = "0123456789abcdefghijklmnopqrstuvwxyz";
   var zeros = "0" * 64;
 
   for (int i = 0; i < whiteSpace.length; i++) {
     var ws = whiteSpace[i];
     Expect.equals(0, int.parse("${ws}0${ws}", radix: 2));
   }
@@ skipping 107 matching lines @@
 
   testBadArguments("0", -1);
   testBadArguments("0", 0);
   testBadArguments("0", 1);
   testBadArguments("0", 37);
 
   // See also int_parse_radix_bad_handler_test.dart
 }
 
 bool isFail(e) => e == "FAIL";