[test-suite] Error when calling test-suite without a full build.
[test-suite] Error when calling test-suite without a full build.

This is still a heuristic, but hopefully stops users from shooting
themselves in the foot.

Fixes #14887

ejgallego/coq,Zimmi48/coq,Zimmi48/coq,coq/coq,SkySkimmer/coq,SkySkimmer/coq,coq/coq,ejgallego/coq,Zimmi48/coq,Zimmi48/coq,coq/coq,SkySkimmer/coq,SkySkimmer/coq,ejgallego/coq,coq/coq,ejgallego/coq