Reverted constant related change (this should be handled togrther with ohter constant related places)

Zend/zend_execute_API.c

@@ -589,7 +589,7 @@ ZEND_API int zval_update_constant_ex(zval *p, zend_class_entry *scope) /* {{{ */
 				return zend_use_undefined_constant(name, ast->attr, p);
 			}
 			zval_ptr_dtor_nogc(p);
-			ZVAL_COPY(p, zv);
+			ZVAL_DUP(p, zv);
 		} else {
 			zval tmp;