test_shapefile.py: Fix or suppress some pylint categories.

[schwehr]

• pointless-statement
• protected-access
• unused-variable

[JamesParrott]

Thanks for this. Ruff and other tools are being run on the Python 3 branch. This would be a good fit there. Is it possible to share the Pylint config, and adjust the settings in it?

This PR fixes all the warnings from running Pylint on test_shapefile.py. But there are 68 other warnings from running Pylint on shapefile.py. I don't mind the single "pointless statement" comment, but I'd prefer to avoid cluttering shapefile.py with comments for every tool.

Wouldn't it be better to use for __ in iterable: pass, or more_itertools.consume, instead of using del to call __del__ each iteration? And just not create the new variable shape in the latter cases?

On the Python 3 branch, lets just add an internal dunder property that allows Reader._offsets to be read by the legacy tests that use that implementation detail, without changing the public API.

[JamesParrott]

I've added a Pylint run (except R,C) on test_shapefile.py to the CI, silenced W0212 using a plug-in for per file settings, and made a few simple changes to the code to avoid these warnings.