Fixing job scheduler test flakiness

Adding a deadline to the test job since timing delay alone can defer the
job indefinitely.
Since deadline is dropped for reschedules, using a new job every time
the job is stopped.

Test: atest FrameworksServicesTests:BackgroundRestrictionsTest

Fixes: 172318004
Change-Id: Ib757def409b4af34fb51ab13e06a38e207d3b332