Each Linux BuildVM clone gets a new SSH host key for the same
NAT IP, causing 'host key has changed' errors with accept-new mode.
After IP detection, ssh-keygen -R removes the old entry from the
CI-local known_hosts file (F:\CI\State\known_hosts by default)
before Phase 4/5 make any SSH connection. The file is created if
it does not exist yet. Windows jobs are unaffected.