Add test for bug #73816

This has been fixed by 0f2cdbf,
add the test case.

Author: nikic

Zend/tests/bug73816.phpt

@@ -0,0 +1,24 @@
+--TEST--
+Bug #73816: Broken eval(anonymous class)
+--FILE--
+<?php
+
+function anon()
+{
+    static $i = 0;
+    return eval(sprintf('return new class { private $prop%s; };', ++$i));
+}
+
+var_dump(anon());
+var_dump(anon());
+
+?>
+--EXPECT--
+object(class@anonymous)#1 (1) {
+  ["prop1":"class@anonymous":private]=>
+  NULL
+}
+object(class@anonymous)#1 (1) {
+  ["prop2":"class@anonymous":private]=>
+  NULL
+}