Fix int.parse bug (dart2js version)

tests/corelib/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);
@@ skipping 76 matching lines @@
   Expect.equals(1, int.parse("+1", radix: 2));
 
   void testFails(String source, int radix) {
     Expect.throws(() { throw int.parse(source, radix: radix,
                                        onError: (s) { throw "FAIL"; }); },
                   (e) => e == "FAIL",
                   "$source/$radix");
     Expect.equals(-999, int.parse(source, radix: radix, onError: (s) => -999));
   }
   for (int i = 2; i < 36; i++) {
-    testFails(i.toRadixString(36), i);
+    testFails(i.toRadixString(36).toLowerCase(), i);
+    testFails(i.toRadixString(36).toUpperCase(), i);
   }
   testFails("", 2);
   testFails("+ 1", 2);  // No space between sign and digits.
   testFails("- 1", 2);  // No space between sign and digits.
   testFails("0x", null);
   for (int i = 2; i <= 33; i++) {
     // No 0x specially allowed.
     // At radix 34 and above, "x" is a valid digit.
     testFails("0x10", i);
   }
@@ skipping 25 matching lines @@
   testBadArguments("0", 0);
   testBadArguments("0", 1);
   testBadArguments("0", 37);
 
   // If handleError isn't an unary function, and it's called, it also throws
   // (either TypeError in checked mode, or some failure in unchecked mode).
   Expect.throws(() => int.parse("9", radix: 8, onError: "not a function"));
   Expect.throws(() => int.parse("9", radix: 8, onError: () => 42));
   Expect.throws(() => int.parse("9", radix: 8, onError: (v1, v2) => 42));
 }