Make './basic_tests.py -- -1' work as a way to run the last test in test_list. (To be used when that test is a local addition that hasn't been committed yet.)
Make './basic_tests.py -- -1' work as a way to run the last test in test_list.
(To be used when that test is a local addition that hasn't been committed yet.)

* subversion/tests/cmdline/svntest/main.py
  (run_one_test):  Allow the test number to be negatiave.

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