The transaction-scoped TRY variant had no production callers — only the
conn-level try-lock (acquireAdvisoryLock) and the blocking xact variant
(acquireAdvisoryXactLockBlocking, used by the admin cancellation path) are in
use. Dropping the dead code removes a foot-gun: a try-lock that silently
fails to acquire inside a transaction would otherwise look like a safe option.