fix xml lib missing

test/script/_debug.php

 #!/usr/bin/env php
 <?php
 
-$xml = simplexml_load_file('../test/output/output.xml');
-$val = $xml->table->row->col[0];
-print(">> $val\n");
\ No newline at end of file
+if (function_exists('simplexml_load_file')) {
+    print("simplexml_load_file missing, pls use 'sudo apt-get install php7.0-simplexml' to install\n");
+}
\ No newline at end of file

test/script/output_style.php

@@ -41,7 +41,7 @@ $arr = explode("\n", $content);
 print(">> $arr[0]\n");
 
 if (function_exists('simplexml_load_file')) {
-    print('simplexml_load_file missing, pls use "sudo apt-get install php7.0-simplexml" to install');
+    print("lib simplexml_load_file missing, pls use 'sudo apt-get install php7.0-simplexml' to install\n");
 } else {
     $output = [];
     exec("$cmd -y ../test/definition/basic.yaml -c 3 -field char,numb -o ../test/output/output.xml -f xml", $output);