Fix Unicode issues in dart2js and dart2dart.

tests/utils/utf8_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.
 
 library utf8_test;
 import 'dart:utf';
 
 String decode(List<int> bytes) => decodeUtf8(bytes);
 
-bool isRunningOnJavaScript() => identical(1, 1.0);
-
 main() {
   // Google favorite: "Îñţérñåţîöñåļîžåţîờñ".
   String string = decode([0xc3, 0x8e, 0xc3, 0xb1, 0xc5, 0xa3, 0xc3, 0xa9, 0x72,
                           0xc3, 0xb1, 0xc3, 0xa5, 0xc5, 0xa3, 0xc3, 0xae, 0xc3,
                           0xb6, 0xc3, 0xb1, 0xc3, 0xa5, 0xc4, 0xbc, 0xc3, 0xae,
                           0xc5, 0xbe, 0xc3, 0xa5, 0xc5, 0xa3, 0xc3, 0xae, 0xe1,
                           0xbb, 0x9d, 0xc3, 0xb1]);
   Expect.stringEquals("Îñţérñåţîöñåļîžåţîờñ", string);
 
   // Blueberry porridge in Danish: "blåbærgrød".
   string = decode([0x62, 0x6c, 0xc3, 0xa5, 0x62, 0xc3, 0xa6, 0x72, 0x67, 0x72,
                    0xc3, 0xb8, 0x64]);
   Expect.stringEquals("blåbærgrød", string);
 
   // "சிவா அணாமாைல", that is "Siva Annamalai" in Tamil.
   string = decode([0xe0, 0xae, 0x9a, 0xe0, 0xae, 0xbf, 0xe0, 0xae, 0xb5, 0xe0,
                    0xae, 0xbe, 0x20, 0xe0, 0xae, 0x85, 0xe0, 0xae, 0xa3, 0xe0,
                    0xae, 0xbe, 0xe0, 0xae, 0xae, 0xe0, 0xae, 0xbe, 0xe0, 0xaf,
                    0x88, 0xe0, 0xae, 0xb2]);
   Expect.stringEquals("சிவா அணாமாைல", string);
 
   // "िसवा अणामालै", that is "Siva Annamalai" in Devanagari.
   string = decode([0xe0, 0xa4, 0xbf, 0xe0, 0xa4, 0xb8, 0xe0, 0xa4, 0xb5, 0xe0,
                    0xa4, 0xbe, 0x20, 0xe0, 0xa4, 0x85, 0xe0, 0xa4, 0xa3, 0xe0,
                    0xa4, 0xbe, 0xe0, 0xa4, 0xae, 0xe0, 0xa4, 0xbe, 0xe0, 0xa4,
                    0xb2, 0xe0, 0xa5, 0x88]);
   Expect.stringEquals("िसवा अणामालै", string);
 
-  if (!isRunningOnJavaScript()) {
-    // DESERET CAPITAL LETTER BEE, unicode 0x10412(0xD801+0xDC12)
-    // UTF-8: F0 90 90 92
-    string = decode([0xf0, 0x90, 0x90, 0x92]);
-    Expect.stringEquals("𐐒", string);
-  } else {
-    print('Skipping non-BMP character test');
-  }
+  // DESERET CAPITAL LETTER BEE, unicode 0x10412(0xD801+0xDC12)
+  // UTF-8: F0 90 90 92
+  string = decode([0xf0, 0x90, 0x90, 0x92]);
+  Expect.equals(string.length, 2);
+  Expect.equals("𐐒".length, 2);
+  Expect.stringEquals("𐐒", string);
 
   // TODO(ahe): Add tests of bad input.
 }