lib-test: Fixed "Trying to allocate 0 bytes" assert-crash caused by recent test-istream changes.
lib-test: Fixed "Trying to allocate 0 bytes" assert-crash caused by recent test-istream changes.

LTD-Beget/dovecot,LTD-Beget/dovecot,LTD-Beget/dovecot,LTD-Beget/dovecot,LTD-Beget/dovecot