test: Do not fail if packet cannot be extended in QUIC multistream test

test: Do not fail if packet cannot be extended in QUIC multistream test

In some specific timings, the qtest_fault_resize_plain_packet function
returns failure as there is not enough space in allocated buffer.

There is no way to recover in this situation, let print
information and keep the test finish instead of failure
in TEST_error() call.

This patch fixes test runs on Windows where I can reproduce
this quite reliably.

Signed-off-by: Milan Broz <gmazyland@gmail.com>
Reviewed-by: Saša Nedvědický <sashan@openssl.org>
Reviewed-by: Norbert Pocs <norbertp@openssl.org>
MergeDate: Thu Mar 19 09:17:59 2026
(Merged from https://github.com/openssl/openssl/pull/30461)