Move admin access check to top of test_langs script

The administrator access check was being performed a little too late in
the test_langs.php script. This could reveal potentially sensitive
information via error messages that are encountered before the admin
check.

admin/test_langs.php

@@ -29,6 +29,8 @@
  */
 require_once( dirname( dirname( __FILE__ ) ) . DIRECTORY_SEPARATOR . 'core.php' );
 
+access_ensure_global_level( config_get_global( 'admin_site_threshold' ) );
+
 if( function_exists( 'xdebug_disable' ) ) {
 	xdebug_disable();
 }
@@ -48,8 +50,6 @@
 unset( $g_skip_lang_load ) ;
 lang_push( 'english' );
 
-access_ensure_global_level( config_get_global( 'admin_site_threshold' ) );
-
 set_time_limit( 0 );
 
 html_page_top();