Add some support for the code-point code-unit distinction.

tests/co19/co19-dart2js.status

 # 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.
 
 
 # Crashes first, please. Then untriaged bugs. There is a section below
 # for co19 bugs.
 [ $compiler == dart2js ]
 Language/03_Overview/1_Scoping_A02_t05: Fail # TODO(ahe): Please triage this failure.
 Language/03_Overview/1_Scoping_A02_t06: Fail # TODO(ahe): Please triage this failure.
@@ skipping 259 matching lines @@
 # Tests that fail because they use the legacy try-catch syntax.
 # See co19 issue 184.
 LibTest/core/List/getRange_A03_t01: Fail, OK
 LibTest/core/List/setRange_A05_t01: Fail, OK
 
 # These tests need to be updated for new optional parameter syntax and semantics, co19 issue 258:
 Language/07_Classes/1_Instance_Methods_A02_t05: Fail, OK
 Language/07_Classes/6_Constructors/1_Generative_Constructors_A13_t01: Fail, OK
 Language/14_Types/5_Function_Types_A01_t21: Fail, OK
 
-LibTest/core/String/charCodes_A01_t01: Fail, OK # co19 issue 289
-
 LibTest/core/Stopwatch/Stopwatch_A01_t01: Fail, OK # co19 issue 297
 LibTest/core/Stopwatch/elapsed_A01_t03: Fail, OK # co19 issue 297
 LibTest/core/Stopwatch/elapsed_A01_t01: Fail, OK # co19 issue 297
 LibTest/core/Stopwatch/elapsed_A01_t02: Fail, OK # co19 issue 297
 LibTest/core/Stopwatch/elapsedInUs_A01_t01: Fail, OK # co19 issue 297
 LibTest/core/Stopwatch/elapsedInMs_A01_t01: Fail, OK # co19 issue 297
 LibTest/core/Stopwatch/start_A01_t01: Fail, OK # co19 issue 297
 LibTest/core/Stopwatch/start_A01_t02: Fail, OK # co19 issue 297
 LibTest/core/Stopwatch/start_A01_t03: Fail, OK # co19 issue 297
 LibTest/core/Stopwatch/stop_A01_t01: Fail, OK # co19 issue 297
@@ skipping 93 matching lines @@
 # can understand so he can file a bug later.
 #
 [ $compiler == dart2js ]
 Language/11_Expressions/11_Instance_Creation/1_New_A01_t04: Fail, OK # co19 issue 241
 Language/11_Expressions/22_Equality_A01_t19: Fail, OK # co19 issue 241
 Language/11_Expressions/22_Equality_A01_t20: Fail, OK # co19 issue 241
 Language/11_Expressions/32_Type_Cast_A01_t04: Fail, OK # co19 issue 241
 
 Language/11_Expressions/22_Equality_A01_t01: Fail, OK # Function declaration takes precedence over function expression.
 Language/11_Expressions/28_Postfix_Expressions_A01_t01: Fail, OK # A map literal cannot start an expression statement.
-LibTest/core/String/String_class_A02_t01: Pass, Fail, OK # issue 6418 compiler cancelled: Unhandled non-BMP character: U+10000
-LibTest/core/String/charCodeAt_A01_t01: Fail, OK # compiler cancelled: Unhandled non-BMP character: U+10000
-LibTest/core/String/charCodes_A01_t01: Fail, OK # compiler cancelled: Unhandled non-BMP character: U+10000
+LibTest/core/String/String_class_A02_t01: Fail, OK # Fixed in co19 version 443
+LibTest/core/RegExp/Pattern_semantics/firstMatch_CharacterClassEscape_A06_t01: Fail, OK # Fixed in co19 version 443
+LibTest/core/RegExp/Pattern_semantics/firstMatch_CharacterClassEscape_A02_t01: Fail, OK # Fixed in co19 version 443
+LibTest/core/RegExp/Pattern_semantics/firstMatch_CharacterClassEscape_A01_t01: Fail, OK # Fixed in co19 version 443
+LibTest/core/RegExp/Pattern_semantics/firstMatch_CharacterClassEscape_A05_t01: Fail, OK # Fixed in co19 version 443
+
 
 Language/06_Functions/1_Function_Declaration_A02_t03: Fail, OK # co19 issue 210
 Language/06_Functions/1_Function_Declaration_A03_t03: Fail, OK # co19 issue 210
 Language/06_Functions/2_Formal_Parameters/2_Optional_Formals_A01_t14: Fail, OK # co19 issue 210
 Language/06_Functions/2_Formal_Parameters/2_Optional_Formals_A01_t15: Fail, OK # co19 issue 210
 Language/11_Expressions/05_Strings/1_String_Interpolation_A01_t09: Fail, OK # co19 issue 210
 
 Language/03_Overview/1_Scoping_A01_t40: Fail, OK # co19 issue 188
 Language/03_Overview/1_Scoping_A01_t41: Fail, OK # co19 issue 188
 
@@ skipping 285 matching lines @@
 Language/14_Types/4_Interface_Types_A10_t01: Fail # http://dartbug.com/5020
 Language/14_Types/4_Interface_Types_A10_t02: Fail # http://dartbug.com/5020
 Language/14_Types/4_Interface_Types_A10_t03: Fail # http://dartbug.com/5020
 Language/14_Types/4_Interface_Types_A10_t04: Fail # http://dartbug.com/5020
 Language/14_Types/4_Interface_Types_A10_t07: Fail # http://dartbug.com/5020
 Language/14_Types/4_Interface_Types_A11_t02: Fail # http://dartbug.com/5020
 Language/14_Types/4_Interface_Types_A12_t09: Fail # http://dartbug.com/5020
 Language/14_Types/4_Interface_Types_A12_t10: Fail # http://dartbug.com/5020
 Language/14_Types/4_Interface_Types_A12_t14: Fail # http://dartbug.com/5020
 Language/14_Types/4_Interface_Types_A12_t16 :Fail # http://dartbug.com/5020