test: Fix run-tests to get along with non-blocking stdout
test: Fix run-tests to get along with non-blocking stdout

Fixes #14214
Closes #14225
moraleslazaro/cockpit,deryni/cockpit,moraleslazaro/cockpit,martinpitt/cockpit,deryni/cockpit,cockpit-project/cockpit,mvollmer/cockpit,cockpit-project/cockpit,martinpitt/cockpit,cockpit-project/cockpit,martinpitt/cockpit,moraleslazaro/cockpit,garrett/cockpit,moraleslazaro/cockpit,mvollmer/cockpit,deryni/cockpit,deryni/cockpit,mvollmer/cockpit,cockpit-project/cockpit,martinpitt/cockpit,garrett/cockpit,mvollmer/cockpit,moraleslazaro/cockpit,garrett/cockpit,cockpit-project/cockpit,deryni/cockpit,moraleslazaro/cockpit,deryni/cockpit,deryni/cockpit,martinpitt/cockpit,moraleslazaro/cockpit,garrett/cockpit,garrett/cockpit,mvollmer/cockpit