Fix the issue that was preventing us from upgrading pytest. pytest does some manipulation of test packages that prevents `pkg_resources` from loading resources from them, but used to contain a workaround for the problem. That workaround was [removed](https://github.com/pytest-dev/pytest/issues/5392) in 4.6.0 as a performance enhancement when pytest switched from `pkg_resources` to `importlib-metadata` for its own entrypoint handling. This tripped up one of our test modules which defined classes that loaded templates from inside a test package. Moving these resources to the parent package fixes the problem.
More and more, `pkg_resources` is being abandoned in favor of `importlib-metadata` and `importlib_resources` as they have a simpler design with much better performance. However, `importlib_resources` doesn't support loading files from any directory which isn't itself a Python package (and doesn't allow direct use of paths including directories within the package). Jinja2 chose a [different approach](https://github.com/pallets/jinja/pull/1082) that we may want to emulate in our resource handling.
Also fixed usage of a removed `pytest.raises()` parameter and a bug in our configuration of the `common/lib` tests that became a problem after the upgrade.
63574e12b8