Reduce the level of logging used in tests

This should avoid running into a bug with printf format specifiers one
windows.

It's also a logical move for actual tests: I used the highest debug
level for discovery, but we don't need that all the time.

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
diff --git a/library/ssl_tls13_server.c b/library/ssl_tls13_server.c
index acb65e3..1dde4ab 100644
--- a/library/ssl_tls13_server.c
+++ b/library/ssl_tls13_server.c
@@ -91,7 +91,7 @@
         return;
     }
 
-    MBEDTLS_SSL_DEBUG_MSG(2, ("No matched ciphersuite, psk_ciphersuite_id=%x, psk_hash_alg=%lx",
+    MBEDTLS_SSL_DEBUG_MSG(1, ("No matched ciphersuite, psk_ciphersuite_id=%x, psk_hash_alg=%lx",
                               (unsigned) psk_ciphersuite_id,
                               (unsigned long) psk_hash_alg));
 }