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/tests/suites/test_suite_ssl.function b/tests/suites/test_suite_ssl.function
index e6c75bf..df9d9bc 100644
--- a/tests/suites/test_suite_ssl.function
+++ b/tests/suites/test_suite_ssl.function
@@ -5070,7 +5070,7 @@
     srv_pattern.pattern = log_pattern;
     options.srv_log_obj = &srv_pattern;
     options.srv_log_fun = mbedtls_test_ssl_log_analyzer;
-    mbedtls_debug_set_threshold(5);
+    mbedtls_debug_set_threshold(1);
 
     options.pk_alg = pk_alg;
 
@@ -5102,7 +5102,11 @@
         ret = mbedtls_ssl_handshake_step(&server.ssl);
     } while (ret == 0 && server.ssl.state == state);
     TEST_EQUAL(ret,  expected_ret);
-    TEST_EQUAL(srv_pattern.counter, 1);
+    /* If we're expected to suceeed and we do, that's enough.
+     * If we're expected to fail, also check it was in the expected way. */
+    if (expected_ret != 0) {
+        TEST_EQUAL(srv_pattern.counter, 1);
+    }
 
 exit:
     mbedtls_test_free_handshake_options(&options);
@@ -5147,7 +5151,7 @@
     srv_pattern.pattern = log_pattern;
     options.srv_log_obj = &srv_pattern;
     options.srv_log_fun = mbedtls_test_ssl_log_analyzer;
-    mbedtls_debug_set_threshold(5);
+    mbedtls_debug_set_threshold(1);
 
     // Does't really matter but we want to know to declare dependencies.
     options.pk_alg = MBEDTLS_PK_ECDSA;