Use server_sm2_cert_der and refresh certs_test_sm.h for record-size SM test

test_record_size_matches_build_message loaded the embedded server_sm2_der
buffer, which is generated from the stale certs/sm2/server-sm2.der (still
the Feb 2023 / Nov 2025 cert). On a minimal SM build the SM TLS handshake
aborts with -151 ASN_AFTER_DATE_E and the test fails. Switch the test to
load server_sm2_cert_der, which tracks the current 2026-2028 SM2 server
cert, and regenerate wolfssl/certs_test_sm.h via gencertbuf.pl so
ca_sm2_der is also refreshed against the in-tree CA cert.

Author: julek-wolfssl

tests/api/test_tls.c

@@ -1197,7 +1197,8 @@ int test_record_size_matches_build_message(void)
                 ExpectIntEQ(test_memio_setup_ex(&test_ctx, &ctx_c, &ctx_s,
                         &ssl_c, &ssl_s, versions[v].client, versions[v].server,
                         (byte*)ca_sm2_der, (int)sizeof_ca_sm2_der,
-                        (byte*)server_sm2_der, (int)sizeof_server_sm2_der,
+                        (byte*)server_sm2_cert_der,
+                        (int)sizeof_server_sm2_cert_der,
                         (byte*)server_sm2_priv_der,
                         (int)sizeof_server_sm2_priv_der), 0);
                 if (versions[v].is_tls13) {