Unit tests: Check for lost resource after failed rollback

Check that when a new resource is added to a stack during an update and it
is unable to be deleted during rollback, that we do not lose track of it
but rather it remains in the template whence we can later attempt again to
delete it.

Change-Id: I83ebbc16c84561b69f9bdb8e7485de85b695c1b8
Related-Bug: #1330016
Merge "Unit tests: Check for lost resource after failed rollback"