Remove support for + prefix in number literals

tests/lib/math/math2_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.
 
 // We temporarily test both the new math library and the old Math
 // class. This can easily be simplified once we get rid of the Math
 // class entirely.
 library math_test;
 import "package:expect/expect.dart";
 import 'dart:math' as math;
@@ skipping 191 matching lines @@
     Expect.equals(0xABCDEF, int.parse("   0x00000ABCDEF   "));
     Expect.equals(-0xabcdef, int.parse("   -0x00000abcdef   "));
     Expect.equals(-0xABCDEF, int.parse("   -0x00000ABCDEF   "));
     Expect.equals(10, int.parse("010"));
     Expect.equals(-10, int.parse("-010"));
     Expect.equals(10, int.parse("   010   "));
     Expect.equals(-10, int.parse("   -010   "));
     Expect.equals(9, int.parse("09"));
     Expect.equals(9, int.parse(" 09 "));
     Expect.equals(-9, int.parse("-09"));
+    Expect.equals(0x1234567890, int.parse("+0x1234567890"));
+    Expect.equals(0x1234567890, int.parse("   +0x1234567890   "));
+    Expect.equals(0x100, int.parse("+0x100"));
+    Expect.equals(0x100, int.parse("   +0x100   "));
+
     Expect.equals(true, parseIntThrowsFormatException("1b"));
     Expect.equals(true, parseIntThrowsFormatException(" 1b "));
     Expect.equals(true, parseIntThrowsFormatException(" 1 b "));
     Expect.equals(true, parseIntThrowsFormatException("1e2"));
     Expect.equals(true, parseIntThrowsFormatException(" 1e2 "));
     Expect.equals(true, parseIntThrowsFormatException("00x12"));
     Expect.equals(true, parseIntThrowsFormatException(" 00x12 "));
     Expect.equals(true, parseIntThrowsFormatException("-1b"));
     Expect.equals(true, parseIntThrowsFormatException(" -1b "));
     Expect.equals(true, parseIntThrowsFormatException(" -1 b "));
     Expect.equals(true, parseIntThrowsFormatException("-1e2"));
     Expect.equals(true, parseIntThrowsFormatException(" -1e2 "));
     Expect.equals(true, parseIntThrowsFormatException("-00x12"));
     Expect.equals(true, parseIntThrowsFormatException(" -00x12 "));
     Expect.equals(true, parseIntThrowsFormatException("  -00x12 "));
     Expect.equals(true, parseIntThrowsFormatException("0x0x12"));
     Expect.equals(true, parseIntThrowsFormatException("0.1"));
     Expect.equals(true, parseIntThrowsFormatException("0x3.1"));
     Expect.equals(true, parseIntThrowsFormatException("5."));
     Expect.equals(true, parseIntThrowsFormatException("+-5"));
     Expect.equals(true, parseIntThrowsFormatException("-+5"));
     Expect.equals(true, parseIntThrowsFormatException("--5"));
     Expect.equals(true, parseIntThrowsFormatException("++5"));
     Expect.equals(true, parseIntThrowsFormatException("+ 5"));
     Expect.equals(true, parseIntThrowsFormatException("- 5"));
     Expect.equals(true, parseIntThrowsFormatException(""));
     Expect.equals(true, parseIntThrowsFormatException("  "));
-    Expect.equals(true, parseIntThrowsFormatException("+0x1234567890"));
-    Expect.equals(true, parseIntThrowsFormatException("   +0x1234567890   "));
-    Expect.equals(true, parseIntThrowsFormatException("+0x100"));
-    Expect.equals(true, parseIntThrowsFormatException("   +0x100   "));
   }
 
   static testMain() {
     testConstants();
     testSin();
     testCos();
     testTan();
     testAsin();
     testAcos();
     testAtan();
     testAtan2();
     testSqrt();
     testLog();
     testExp();
     testPow();
     testParseInt();
   }
 }
 
 main() {
   MathLibraryTest.testMain();
 }