cmake: The `svn-javahl.jar` file now includes test classes to ensure results
consistent with autoconf builds. As the result, the junit jar file is now
required when building javahl with cmake as well. See also r1936939.

* CMakeLists.txt
  (JUNIT_JAR): Add a file existent check.
  (svn-javahl): Add the test source files to SOURCES.
  (svn-javahl-tests): Remove. This target is no longer needed.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1937024 13f79535-47bb-0310-9956-ffa450edef68