[php-src] PR #23597: session: close save handler before re-initializing an active session

Pull Request: https://github.com/php/php-src/pull/23597 Author: iliaal php_session_initialize() set the status to active and called the save handler's open() and read() without first closing a session that was already active, so session_reset() on an open session issued a second open() with no intervening close(). Aborting the active session first pairs every open() with a close(). The test asserts the handler's own call log, which is open, read, open, read before the change and open, read, close, open, read after.