clang/tests

Gating testplans for Clang

The tests for clang are in a separate repo: https://src.fedoraproject.org/tests/clang This directory should contain only fmf plans (such as build-gating.fmf) which import the tests from the tests repo. This can be done using the "url" parameter of the plan's "discover" step. Reference: https://tmt.readthedocs.io/en/stable/spec/plans.html#fmf