Fix problem of `--stderr` with `--tap` or `--testdox` options

I don't think this pull request is the best solution to fix #1455, but I'm sure it solves the problem.

Actually, the main problem, IMO, is because there is no centralized point to create printers instances. `PHPUnit_TextUI_Command` creates and configures printers objects but `PHPUnit_TextUI_TestRunner` too. 

I will be glad to create a Factory for these printers but it requires a quite of change.

PS.: I can not test this, because seems that PHPT does not recognize STDERR.