[Forwardport] Fix unstable session manager

[jignesh-baldha]

Original Pull Request

#14973

Description

Fix of the unstable behaviour of the session management with high volume of concurrent sessions.

Fixed Issues

1. Concurrent (quick reload) requests on checkout cause cart to empty - related to session_regenerate_id #12362: Concurrent (quick reload) requests on checkout cause cart to empty - related to session_regenerate_id

Manual testing scenarios

1. Reach the checkout page with products in the cart
2. Press CMD+R or ALT+F5 multiple times to refresh the page, after the fix the user is not being logged out and redirected to the empty cart page.

We already deployed the fix on our high traffic website and the issue is fixed.

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[magento-engcom-team]

Hi @jignesh-baldha. Thank you for your contribution
Here is some useful tips how you can test your changes using Magento test environment.
Add the comment under your pull request to deploy test or vanilla Magento instance:

• @magento-engcom-team give me test instance - deploy test instance based on PR changes
• @magento-engcom-team give me {$VERSION} instance - deploy vanilla Magento instance

For more details, please, review the Magento Contributor Assistant documentation

[magento-engcom-team]

Hi @jignesh-baldha. Thank you for your contribution.
We will aim to release these changes as part of 2.3.0.
Please check the release notes for final confirmation.

[elioermini]

Hi @magento-engcom-team I'd like to keep credit of the PR as what @jignesh-baldha did was using the automated tool to forward port while I spent weeks for the solution.

[gabrieljadeau]

Somebody could provide the patch for m2.2.5?

THanks :)

[kennedyabitbol]

Seems to be confirmed on 2.2.4, ENGCOM-2794 works fine.