Refine test code and test scripts

Change client test code to support rsa pss signatures
Add test cases for rsa pss signature in ssl-opt.sh

Signed-off-by: XiaokangQian <xiaokang.qian@arm.com>
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 4ada536..91cc5b6 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -6389,6 +6389,12 @@
     MBEDTLS_TLS13_SIG_ECDSA_SECP384R1_SHA384,
 #endif /* MBEDTLS_SHA512_C && MBEDTLS_ECP_DP_SECP384R1_ENABLED */
 #endif /* MBEDTLS_ECDSA_C */
+
+    /* RSA algorithms */
+#if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT)
+    MBEDTLS_TLS13_SIG_RSA_PSS_RSAE_SHA256,
+#endif
+
     MBEDTLS_TLS13_SIG_NONE
 };
 #endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */