Factor out the 'run svn' command in the reintegrate merge tests. I verified
 that this
  is a no-op by comparing the verbose output before and after:
it is unchanged apart from line numbers.

* subversion/tests/cmdline/merge_reintegrate_tests.py
  (run_reintegrate,
   run_reintegrate_expect_error,
   run_and_verify_reintegrate): New, factored out...
  (...elsewhere...): ... from here.

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1437228 13f79535-47bb-0310-9956-ffa450edef68