[Session] SessionInterface should have a destroy() method. Currently there is no way to simply destroy a session #12375
Description
SessionInterface::invalidate() method starts a new session after invalidating the current one.
When PdoSessionHandler is used, this creates unnecessary db entries.
In my case sessions have long gc_maxlifetime (because they are used by mobile clients), so there is no way to close a session without generating implicit redundant db rows which stays there for a long time.