Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=56012
Imports from unnamed packages are now explicitly illegal

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1559419 13f79535-47bb-0310-9956-ffa450edef68
Remove unused code

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1559420 13f79535-47bb-0310-9956-ffa450edef68
Add the test case from bug 56031 as it suggested there may be further issues - there were not

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1559424 13f79535-47bb-0310-9956-ffa450edef68