MXS-2900 Rename maxscale-system-test directory to system-test

A link with the old directory name is provided.

system-test/rwsplit_php_stmt.php

@@ -0,0 +1,19 @@
+<?php
+$options = [
+    PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
+    PDO::ATTR_EMULATE_PREPARES => false,
+];
+
+$host=$argv[1];
+$port=$argv[2];
+$user=$argv[3];
+$pass=$argv[4];
+
+$dsn = "mysql:host=".$host.";port=".$port.";dbname=information_schema";
+$dbh = new PDO( $dsn, $user, $pass, $options );
+$res = $dbh
+    ->query( "SELECT COLLATION_NAME FROM COLLATIONS" )
+    ->fetch( PDO::FETCH_COLUMN );
+
+var_dump( $res );
+