Testing doze jobs controller changes

Added tests for the following jobscheduler changes:
 - A new api flag to indicate that a job is important and should be
 granted leniency from doze restrictions
 - Background tasks will be delayed when the device comes out of doze to
 make sure foreground and important tasks can use system resources.

Test: cts-tradefed run singleCommand cts-dev -m JobScheduler -t \
android.jobscheduler.cts.DeviceIdleJobsTest

Bug: 64291952
Bug: 64071030

Change-Id: Ie9f2b1d62038b982664e60955b0bb890784bcb05
8 files changed