Re-add check for non-NULL

Author: TimWolla

Zend/zend_opcode.c

@@ -152,7 +152,11 @@ ZEND_API void zend_function_dtor(zval *zv)
 		ZEND_ASSERT(function->type == ZEND_INTERNAL_FUNCTION);
 		ZEND_ASSERT(function->common.function_name);
 		zend_string_release_ex(function->common.function_name, 1);
-		zend_hash_release(function->common.attributes);
+
+		if (function->common.attributes) {
+			zend_hash_release(function->common.attributes);
+			function->common.attributes = NULL;
+		}
 
 		/* For methods this will be called explicitly. */
 		if (!function->common.scope) {