Test::Builder and Test::Builder::Tester Ports

[Chromatic]

Hi everyone,

Prompted by Geoff Young and Jeff Horwitz, I've written and checked in
pure Parrot ports of Test::Builder and Test::Builder::Tester. They're
complete enough to work, though they're missing a couple of nice
features I haven't figured out how to add yet.

The next goal is to port Test::More, then Parrot::Test. Patches,
suggestions, comments, and questions welcome.

Not Jeff or Geoff,
-- c