Since 19252e8ec9 we reject Python 2 during build configuration. Now that the
dust on the buildfarm has settled, remove regression testing infrastructure
dealing with differing output between Python 2 / 3.
Reviewed-By: Peter Eisentraut <peter@eisentraut.org>
Reviewed-By: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/20211031184548.g4sxfe47n2kyi55r@alap3.anarazel.de
This changes a bunch of incidentially used constructs in the PL/Python
regression tests to equivalent constructs in cases where Python 3 no longer
supports the old syntax. Support for older Python versions is unchanged.
of the previous monolithic setup-create-run sequence, that was apparently
inherited from a previous test infrastructure, but makes working with the
tests and adding new ones weird.
