containers/unit-tests: Show test-suite.log on check failure
containers/unit-tests: Show test-suite.log on check failure

Same approach as with `check-memory` failures, to get more details about
hard to reproduce failures.

mvollmer/cockpit,garrett/cockpit,deryni/cockpit,deryni/cockpit,garrett/cockpit,deryni/cockpit,mvollmer/cockpit,martinpitt/cockpit,garrett/cockpit,martinpitt/cockpit,cockpit-project/cockpit,deryni/cockpit,mvollmer/cockpit,martinpitt/cockpit,deryni/cockpit,mvollmer/cockpit,martinpitt/cockpit,cockpit-project/cockpit,cockpit-project/cockpit,cockpit-project/cockpit,mvollmer/cockpit,deryni/cockpit,martinpitt/cockpit,garrett/cockpit,cockpit-project/cockpit,garrett/cockpit,deryni/cockpit