* Created common configuration file (tests/main.fmf) to take advantage
of fmf elasticity and inheritance.
* Cleanup and simplify all tests metadata.
* Remove no longer needed adjustments from plans
* Support lld tests in s390x for llvm >= 18
According to the documentation, this parameter "disable removal of
dependencies that are no longer used". However, there are no lld
dependencies required in the test that could be impacted.
The most important package is binutils, which was manually installed and
shouldn't be removed automatically. If the package does so, that would
be a bug.
