Deprecate implicit commit-on-destruct

Postponed on #3406985: Convert all transactions in core to use explicit ::commitOrRelease()

Problem/Motivation

Follow up of #3398767: Allow returning explicitly to the prior nesting level in transactions (aka allow explicit COMMIT in Transaction objects) and #3406985: Convert all transactions in core to use explicit ::commitOrRelease().

Proposed resolution

In this issue :

• Deprecate implicit commit on Transaction destruction.
• Deprecate for removal the methods introduced in #3405976: Transaction autocommit during shutdown relies on unreliable object destruction order (xdebug 3.3+ enabled):
  • Connection::commitAll()
  • Database::commitAllOnShutdown()
  • TransactionManagerBase::commitAll()

Remaining tasks

User interface changes

No

API changes

No

Data model changes

No

Release notes snippet