Rename functions and add test messages

Change-Id: Iab51b031ae82d7b2d384de708858be64be75f9ed
Signed-off-by: XiaokangQian <xiaokang.qian@arm.com>
diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index 295ff9f..ca57114 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -2448,7 +2448,7 @@
  *                          the extension.
  */
 MBEDTLS_CHECK_RETURN_CRITICAL
-int mbedtls_ssl_tls13_write_pre_shared_key_ext_without_binders(
+int mbedtls_ssl_tls13_write_identities_of_pre_shared_key_ext(
     mbedtls_ssl_context *ssl,
     unsigned char *buf, unsigned char *end,
     size_t *out_len, size_t *binders_len );