Fix unboxing warning

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1547846 13f79535-47bb-0310-9956-ffa450edef68
Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=55837
getRealPath() should return a result for resources that don't exist where possible
Add some unit tests to check this.


git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1547848 13f79535-47bb-0310-9956-ffa450edef68