Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=47919
Extend the information logged when Tomcat starts to optionally include (enabled by default) the values of key environment variables.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1630110 13f79535-47bb-0310-9956-ffa450edef68