When older ant version is used to build/test nashorn, we get this error:

The <property> type doesn't support nested text data ("${run.te...jvmargs}").

Coleen suggested the following change fixes this issue:

hg diff
diff -r 41a212ea8c0c make/build.xml
--- a/make/build.xml Thu Mar 28 20:48:25 2013 +0530
+++ b/make/build.xml Fri Mar 29 18:18:53 2013 +0530
@@ -56,7 +56,7 @@
   <target name="init" depends="init-conditions, init-cc">
 
  <!-- extends jvm args -->
- <property name="run.test.jvmargs">${run.test.jvmargs.main} ${run.test.cc.jvmargs}</property>
+ <property name="run.test.jvmargs" value="${run.test.jvmargs.main} ${run.test.cc.jvmargs}"/>
  <property name="run.test.jvmargs.octane" value="${run.test.jvmargs.octane.main} ${run.test.cc.jvmargs}" />
 
     <echo message="run.test.jvmargs=${run.test.jvmargs}"/>

The fix was confirmed by Kumar as well.