We've had a couple of occasions where release builds were mistakenly re-built, which messes up the test reports for the release. Prevent this by terminating the build with an error if the output directory already exists.
Sent patch: https://lore.kernel.org/yocto-patches/20260525210708.2918572-1-yoann.congal@smile.fr/T/#mdfc70f6005723d63d1509d279e91522c4a2d26ac
Patch merged: https://git.yoctoproject.org/yocto-autobuilder2/commit/?id=a999d97e0aab0059ee6dd25432740660511e6db2