[infer][java] Add an example of an ant project in the repository

Summary:
@public
Adds a small example of a Ant project in order to test that there is not regresssion when modifying the toplevel scripts

Test Plan:
  cd infer/tests/codetoanalyze/java/infer
  ant clean && infer -- ant compile

infer/tests/codetoanalyze/java/infer/build.xml

@@ -0,0 +1,20 @@
+<project default="compile">
+
+    <target name="clean">
+        <delete dir="ant_out"/>
+    </target>
+
+    <target name="compile">
+        <mkdir dir="ant_out"/>
+        <javac srcdir="." destdir="ant_out" includeantruntime="false">
+            <bootclasspath>
+                <pathelement location="../../../../lib/java/android/android-19.jar"/>
+            </bootclasspath>
+            <classpath>
+              <pathelement location="../../../dependencies/java/jackson/jackson-2.2.3.jar"/>
+              <pathelement location="../../../../../dependencies/java/jackson/jackson-2.2.3.jar"/>
+            </classpath>
+        </javac>
+    </target>
+
+</project>