Martin, this change has been specifically requested by me to better organise all the support code that ISN'T in test.support.

That file is already huge, and I'm not going to make it even bigger with all the test infrastructure needed for generating packaging heirarchies and zip files and invoking Python subprocesses in various ways.

However, that support code *does* need to be made more discoverable (so we stop reinventing these wheels badly).

A package with the current support.py as its __init__.py is the obvious solution.