disable a bunch of caches, just so we've tried that as well

build.xml

@@ -1665,6 +1665,8 @@ ${antunit.reports}
           <sysproperty key="tests.and.ant.share.classloader"
                        value="${tests.and.ant.share.classloader}"/>
           <sysproperty key="java.io.tmpdir" file="${build.junit.tmpdir}"/>
+          <sysproperty key="sun.io.useCanonCaches" value="false"/>
+          <sysproperty key="sun.io.useCanonPrefixCache" value="false"/>
           <classpath>
             <path refid="tests-runtime-classpath"/>
             <pathelement location="${junit.collector.dir}"/>