fix: Replace macro use in ordered_float tests

[tpoliaw]

The tests make use of the py_run macro which is only available with the
macros feature enabled.

While the py_run macro supports a wider range of requirements, the way
it is used in these tests is straightforward enough that it can be
replaced with a local function to prevent the macros feature needing to
be enabled.

[tpoliaw]

Probably too late, I just read through the related comments on #5344 and I still think this is ok as a stand-alone change. The tests rely on the macro so requiring it makes some sense.

Would it be better to replace the macro uses so the tests run with no other features enabled or is it still clearer to use the shorthand version?

[tpoliaw]

Replacing the macro didn't look too bad so is possibly the better approach so the tests aren't skipped unexpectedly.

[davidhewitt]

Thanks very much for this! Doing this got me experimenting, IIRC we gated py_run! behind the macros feature to avoid the optional dependencies.

Maybe we can simplify and do something like #5608, and then always allow py_run! macro to be defined?