The ring tests used 127.0.0.1:18889 as an unreachable peer, but its gRPC
port 28889 is a common filer port: on a shared CI host a live filer there
accepted the forwarded exclusive create, and
TestCreateEntryExclusiveLeavesNonOwner failed. The peer now listens on a
port the test owns and drops every connection.
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>