Properly delete %TEMP%/ser{number}.tmp temporary file that was used to test serialization of a Principal.

On Windows the test could not delete the file, because FileInputStream has not been properly closed after reading. Thus rerunning the testsuite left a bunch of such files in the %TEMP% directory.

The file is now created in output/tmp instead of the system temporary directory.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1577714 13f79535-47bb-0310-9956-ffa450edef68