Integration tests should delete jobs whenever they delete pools

[BMurri]

Describe the bug
In TES's current Azure Batch usage pattern, every pool has exactly one matching job. In batch, those are separate entities, and deleting one does not cause the deletion of the other (unless the creating TES instance is still running, in which case it will delete items who's partner "disappears" unexpectedly). That leaves jobs that have to be cleaned up manually later on.

Steps to Reproduce
Use a batch account for a while with several resource groups.
Delete those resource groups. (order of these first two can be intermixed with various RGs).
Note the number of pools and jobs.
Run the test IntegrationTests.DeleteOldBatchPoolsAsync from TriggerService.Tests and wait 5 minutes.
Note that the number of jobs remains the same, while the number of pools has diminished.

Expected behavior
Pools and jobs would be deleted together.