tests: test_config: move tests (#6796)
tests: test_config: move tests (#6796)

Originally added in a2891420d (with `TestRootdir`), but then
accidentally moved to `TestOverrideIniArgs` in 802755cee.
nicoddemus/pytest,alfredodeza/pytest,The-Compiler/pytest,nicoddemus/pytest,Akasurde/pytest,The-Compiler/pytest,pytest-dev/pytest,RonnyPfannschmidt/pytest,markshao/pytest