Add pre-flight check for pending jobs before running upgrade

[NateWr]

Describe the problem
When running an upgrade, we may run into odd bugs if there are pending jobs. Consider the following scenario:

1. My 3.4 install has 10 pending jobs, MyExampleJob, in the queue.
2. I run an upgrade to 3.5.
3. The code in 3.5 has changed in some way that means MyExampleJob no longer exists in the code base.
4. The job runner tries to run one of the pending jobs, MyExampleJob, and fails.

Describe the solution you would like to see
Add a pre-flight check to the upgrade process that detects pending jobs and tells the upgrader to run them on the old code base before upgrading.

Additional information
Comment form @touhidurabir:

Not just a case when a job class got removed , but for an existing one when the object data changed as a result the store serialized payload unable to satisfy the current structure so the job will continue to fail after upgrade . This will have high impact for important jobs

This will first become a problem with 3.5, because that will be the first version when a pending job from an older version may be in the queue.

[touhidurabir]

Closing this in favour of Add unit test for each queue jobs class which seems to be more of an appropriate and better approach. More detail reasoning and discussion at Right approach to handle pending queue jobs at upgrade which lead to this decision .