CLEANUP: tests: removed completely obsolete test files

CLEANUP: tests: removed completely obsolete test files

A number of config files were present in the tests/ directory and which
would either test features that are easier to test using more recent files
or test obsolete features. All of them emit tons of useless warnings, and
instead of fixing them, better remove them since they have never been used
in the last 10 years or so.

The remaining files may still emit warnings and require some fixing but
they provide some value for some tests.