Have testing.RunTests run the tests we find with their setup methods.

Hi,

This patch fixes logging with T().Logf et al by running each test with their own T in testing.RunTests. This has a few benefits, chief among them that if a suite or suite generating test function fails, output from all suites is not printed - only the failed individual tests, complete with nice test names and everything :) Makes my life much better! If I can do anything to help this get merged so I can use it at work, please let me know.

Thanks,
Sean