test_runner: do not invoke after hook when test is empty
Fixes: https://github.com/nodejs/node/issues/51371 (recreated because apparently if you force push on a closed PR it cannot be reopened)
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Fixes: https://github.com/nodejs/node/issues/51371 (recreated because apparently if you force push on a closed PR it cannot be reopened)