[php-src] Issue #15135: session.lazy_write only implemented if user defines custom handler with updateTimestamp method - Incorrect behavior

Issue: https://github.com/php/php-src/issues/15135 Author: shimscharf ### Description The following code: https://github.com/php/php-src/blob/21e01f3e70308824169632d5a16047f9df52fac9/ext/session/session.c#L515-L522 Will not call updateTimestamp unless PS(mod)->s_update_timestamp exists & is different to the inbuilt updateTimestamp function (php_session_update_timestamp defined in https://github.com/php/php-src/blob/21e01f3e70308824169632d5a16047f9df52fac9/ext/session/session.c#L1105). It will always call the standard inbuilt file write handler instead. Given that session.lazy_write defaults to 1 --> True, the expectation is that the session file will not be overwritten if there isn't a change in session value. But this will always happen unless there is a defined custom handler. ### PHP Version PHP 8.2 ### Operating System Ubuntu 22.04 LTS