Extend a 1.6-to-wcng upgrade test.
Extend a 1.6-to-wcng upgrade test.

* subversion/tests/cmdline/upgrade_tests.py
  (simple_checksum_verify): New.
  (replaced_files): Verify checksums.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion