Rev the version of apache ant in third_party to 1.8.4. This will fix an issue with

compiler/dart-compiler.gyp

 # 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.
 
 {
   'includes': [
     'sources.gypi',
     'test_sources.gypi',
   ],
   'targets': [
@@ skipping 35 matching lines @@
           ],
           'outputs': [
             '<(INTERMEDIATE_DIR)/<(_target_name)/tests.jar',
             '<(PRODUCT_DIR)/analyzer/bin/dart_analyzer',
             '<(PRODUCT_DIR)/analyzer/bin/dart_analyzer.bat',
             '<(PRODUCT_DIR)/analyzer/util/analyzer/dart_analyzer.jar',
             '<(PRODUCT_DIR)/analyzer/util/analyzer/args4j/2.0.12/args4j-2.0.12.jar',
             '<(PRODUCT_DIR)/analyzer/util/analyzer/guava/r09/guava-r09.jar',
           ],
           'action' : [
-            '../third_party/apache_ant/v1_7_1/bin/ant<(script_suffix)',
+            '../third_party/apache_ant/1.8.4/bin/ant<(script_suffix)',
             '-f', 'dart_analyzer.xml',
             '-Dbuild.dir=<(INTERMEDIATE_DIR)/<(_target_name)',
             '-Ddist.dir=<(PRODUCT_DIR)/analyzer',
             'clean',
             'dist',
             'tests.jar',
           ],
           'message': 'Building dart_analyzer.',
         },
         {
           'action_name': 'copy_tests',
           'inputs': [ '<(INTERMEDIATE_DIR)/<(_target_name)/tests.jar' ],
           'outputs': [ '<(PRODUCT_DIR)/analyzer/dart_analyzer_tests.jar' ],
           'action': [ 'cp', '<@(_inputs)', '<@(_outputs)' ]
         },
       ],
     },
     {
       # GYP won't generate a catch-all target if there's only one target.
       'target_name': 'dummy',
       'type': 'none',
     },
   ],
 }