Add a new op-depth test, verifying move behavior before and after an
op_root only commit.

* subversion/tests/libsvn_wc/op-depth-test.c
  (nested_move_commit): New test.
  (test_list): Add test as XFail.

* subversion/tests/libsvn_wc/utils.c
  (sbox_wc_commit_ex): New function, allowing multiple targets and
    an explicit depth.
  (sbox_wc_commit): Implement on top of sbox_wc_commit_ex.

* subversion/tests/libsvn_wc/utils.h
  (sbox_wc_commit_ex): New function.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1430376 13f79535-47bb-0310-9956-ffa450edef68