FWIW I have no principled opinion about big vs. small test.support module, as this is purely internal code.

The reasons for this proposal as I understand them are:
- One module for script helpers, one module for package creation, etc. are not bad.
- We don’t really want to spend time and thought cleaning up test.support, but it be good to stop adding to the mess.
- Making it easier to find that some function already exists (e.g. script helpers weren’t known by all core devs) would be good.

ISTM that moving support.py to support/__init__.py and moving script_helper.py and friends to support/*.py is a quick and efficient way to address these points and make our lives a little easier:
- Script helpers, package helpers, etc. continue to be in their own file.
- Time is not lost trying to do an upfront cleanup of test.support.
- Developers looking at the test.support package are more likely to have a look at the dosctrings of the other helper modules than they do currently, and thus don’t reinvent the same helpers.