Reduce test verbosity on failure

The tests should stop attempting any queries after the first failure.

maxscale-system-test/mxs1985_kill_hang.cpp

@@ -17,11 +17,11 @@ int main(int argc, char *argv[])
     TestConnections test(argc, argv);
     vector<thread> threads;
 
-    for (int i = 0; i < 20; i++)
+    for (int i = 0; i < 20 && test.global_result == 0; i++)
     {
         threads.emplace_back([&, i]()
         {
-            while (running)
+            while (running && test.global_result == 0)
             {
                 MYSQL* c = test.maxscales->open_rwsplit_connection();
 

maxscale-system-test/rw_select_insert.cpp

@@ -181,7 +181,7 @@ int main(int argc, char *argv[])
 
     get_global_status_allnodes(&selects[0], &inserts[0], Test->repl, silent);
 
-    for (i = 0; i < 100; i++)
+    for (i = 0; i < 100 && Test->global_result == 0; i++)
     {
         Test->set_timeout(20);
         Test->try_query(Test->maxscales->conn_rwsplit[0], "select * from t1;");
@@ -200,7 +200,7 @@ int main(int argc, char *argv[])
     get_global_status_allnodes(&selects[0], &inserts[0], Test->repl, silent);
     Test->tprintf("Doing 100 inserts\n");
 
-    for (i = 0; i < 100; i++)
+    for (i = 0; i < 100 && Test->global_result == 0; i++)
     {
         Test->set_timeout(20);
         Test->try_query(Test->maxscales->conn_rwsplit[0], "insert into t1 values(1);");

maxscale-system-test/ses_bigmem.cpp

@@ -23,7 +23,7 @@ int main(int argc, char *argv[])
 
     for (int j = 0; j < r; j++)
     {
-        for (int i = 0; i < iterations; i++)
+        for (int i = 0; i < iterations && Test->global_result == 0; i++)
         {
             Test->set_timeout(10);
             Test->try_query(Test->maxscales->routers[0][j], (char*) "set autocommit=0;");