Can't switch to Writer once getOutputStream() has been called.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1513278 13f79535-47bb-0310-9956-ffa450edef68
Remove some unused code and simplify the test.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1513280 13f79535-47bb-0310-9956-ffa450edef68