skip test with openssl client because it will timeout with certain seed due to an openssl bug

Signed-off-by: Zhangsen Wang <zhangsen.wang@arm.com>
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index 230f232..bb01383 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -9189,6 +9189,9 @@
             -c "fragmenting handshake message" \
             -C "error"
 
+## the test below will time out with certain seed. 
+## The cause is an openssl bug (https://github.com/openssl/openssl/issues/18887)
+skip_next_test
 requires_config_enabled MBEDTLS_SSL_PROTO_DTLS
 requires_config_enabled MBEDTLS_RSA_C
 requires_config_enabled MBEDTLS_ECDSA_C