Add more comprehensive unit tests for SimpleLog, including the ability
to serialize and deserialize instances.
This work will form the basis for making similar changes to the other
Log implementations (and their corresponding test cases).
git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/logging/trunk@138990 13f79535-47bb-0310-9956-ffa450edef68
