Sync the 1.6.x-issue3646 branch with the 1.6.x branch.

* subversion/tests/cmdline/merge_tests.py: Resolve conflicts in this file.


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.6.x-issue3646@1002684 13f79535-47bb-0310-9956-ffa450edef68