Fix PHP testsuite check::get() helper

This was trying to return a reference, but that doesn't actually work
for all the things it's used for, and none of the uses require the
return value to be a reference.

Examples/test-suite/php/tests.php

@@ -105,7 +105,7 @@ class check {
     else $_GLOBALS[$var]=$value;
   }
 
-  static function &get($var) {
+  static function get($var) {
     $func=$var."_get";
     if (self::GETSET) return $func();
     else return $_GLOBALS[$var];