Extends shortened representation of numbers to negative numbers.

tests/compiler/dart2js/number_output_test.dart

 // Copyright (c) 2015, 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 "package:async_helper/async_helper.dart";
 import 'memory_compiler.dart';
 
 const MEMORY_SOURCE_FILES = const {
     'main.dart': '''
         main() {
           print(12300000);
           print(1234567890123456789012345);
           print(double.MAX_FINITE);
+          print(-22230000);
         }'''};
 
 void test({bool minify}) {
   OutputCollector collector = new OutputCollector();
   var compiler = compilerFor(MEMORY_SOURCE_FILES,
                              outputProvider: collector,
                              options: minify ? ['--minify'] : []);
   asyncTest(() => compiler.run(Uri.parse('memory:main.dart')).then((_) {
     // Check that we use the shorter exponential representations.
     String jsOutput = collector.getOutput('', 'js');
+    print(jsOutput);
 
     if (minify) {
       Expect.isTrue(jsOutput.contains('123e5')); // Shorter than 12300000.
       Expect.isFalse(jsOutput.contains('12300000'));
+      Expect.isTrue(jsOutput.contains('-2223e4')); // Shorter than -22230000.
+      Expect.isFalse(jsOutput.contains('-22230000'));
     } else {
       Expect.isTrue(jsOutput.contains('12300000'));
+      Expect.isTrue(jsOutput.contains('-22230000'));
     }
     Expect.isTrue(jsOutput.contains('12345678901234568e8'));
     Expect.isTrue(jsOutput.contains('17976931348623157e292'));
     Expect.isFalse(jsOutput.contains('1234567890123456789012345'));
     // The decimal expansion of double.MAX_FINITE has 308 digits. We only check
     // for its prefix.
     Expect.isFalse(jsOutput.contains('179769313486231570814527423731'));
   }));
 }
 
 main() {
   test(minify: true);
   test(minify: false);
 }