kqueue notify: Don't assert-cras if kevent() returns multiple events for the same io.
kqueue notify: Don't assert-cras if kevent() returns multiple events for the same io.

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jwm/dovecot-notmuch,jwm/dovecot-notmuch,jkerihuel/dovecot,jkerihuel/dovecot,jkerihuel/dovecot,jwm/dovecot-notmuch,jwm/dovecot-notmuch,jkerihuel/dovecot,jkerihuel/dovecot,jwm/dovecot-notmuch