Revert "Delete classes that are deprecated for six years."

This reverts commit 745ca05dccf5cc907e43a58142bb8be97da2b78f. The
deletion of the classes causes some problems for users (see
https://groups.yahoo.com/neo/groups/junit/conversations/topics/24572).
I restore the classes and let the constructors throw exceptions with
a hint for the migration in the following commit.