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

compiler/dart_analyzer.xml

 <!--
   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.
  -->
 <project default="dist">
   <import file="sources.xml"/>
   <import file="test_sources.xml"/>
 
   <!--
@@ skipping 56 matching lines @@
     -->
     <mkdir dir="${build.classes.dir}"/>
 
     <javac destdir="${build.classes.dir}"
            sourcepath=""
            srcdir="java"
            includes="${java_sources}"
            fork="true"
            debug="true"
            source="1.6"
-           target="1.6">
+           target="1.6"
+           includeAntRuntime="false">
       <classpath refid="classpath.compile"/>
     </javac>
     <!--
       Copy all non-java resources.
     -->
     <copy todir="${build.classes.dir}">
       <filelist refid="java_resources"/>
     </copy>
   </target>
 
   <!--
     We rely on GYP to call these targets when dependencies change, hence this
     ant file cannot be used standalone.
   -->
   <target name="compile-tests" depends="compile" description="Compiles all of the java tests and copies the resources to the test classes directory." >
     <mkdir dir="${build.test.classes.dir}"/>
     <javac destdir="${build.test.classes.dir}"
            sourcepath=""
            srcdir="javatests"
            includes="${javatests_sources}"
            excludes="com/google/dart/compiler/vm/**"
            fork="true"
            debug="true"
            source="1.6"
-           target="1.6">
+           target="1.6"
+           includeAntRuntime="false">
       <classpath refid="classpath.compile.tests"/>
     </javac>
     <!--
       Copy the non-java resources.
     -->
     <copy todir="${build.test.classes.dir}">
       <filelist refid="javatests_resources"/>
     </copy>
   </target>
 
@@ skipping 66 matching lines @@
 
   <target name="clean" description="Deletes the build output directory.">
     <delete dir="${build.dir}"/>
     <delete dir="${dist.dir}"/>
   </target>
 
   <target name="tests.jar" depends="compile-tests">
     <jar destfile="${build.dir}/tests.jar" basedir="${build.test.classes.dir}"/>
   </target>
 </project>