Do not require JUnit to build JavaHL; only to test it.

* subversion/bindings/javahl/tests/org/apache/subversion/javahl/UtilTests.java:
   Do not impoet org.junit.Assert.
  (UtilTests.testFileDiff, UtilTests.testFileMerge): Update assertions.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1535603 13f79535-47bb-0310-9956-ffa450edef68