Export archive to a temporary file name

The archive is exported to a file with the same name as the archive in the temporary directory. That file is set to be deleted when the JVM exits. However, if there is more than one deployment in the same test suite that uses the same test name (typically test.war), then the second deployment will fail because there is a file in the way.

The expected behavior is that the archive is exported to a unique temporary file. It shouldn't matter what the name of the file is as its purpose is to pass the archive contents to Jetty to be extracted.