No exception on `mysqli::rollback` when transaction is no longer active

Description

Repro steps:

1. have an open mysqli connection
2. start transaction using mysqli::begin_transaction
3. run some query like analyze table xx, this is "administrative statement" [1] which implicit autocommit
4. rollback transaction using mysqli::rollback and notice no exception is thrown

Since PHP 8.0, PDO checks if a transaction is active and throws an exception: PDOException: There is no active transaction

mysqli must throw the same exception as well.

Related MariaDB tickets:

• https://jira.mariadb.org/browse/MDEV-28126
• https://jira.mariadb.org/browse/MDEV-32652

[1] docs https://dev.mysql.com/doc/refman/8.0/en/implicit-commit.html and repro: https://dbfiddle.uk/coUjimLq

PHP Version

7.4 - master

Operating System

any

mysqli::rollback のエントリーポイントから始め、issue に記載されている begin_transaction、administrative-statement、rollback のシーケンスを再現します。トランザクション状態の動作を PHP 8 の PDO の例外動作と比較し、トランザクションがアクティブでなくなった場合に rollback が例外を報告することを示すカバレッジを追加します。