Moved BatteryStats and AppOps wakelock updates to the notifier thread

We are moving the tasks performed on AppOpsManager and BatteryStats to
the handler thread to improve the latency of acquiring and releasing
the wakelocks.

This CL was originally merged and then reverted: ag/27435252 because of
a regression that was introduced in Notifier::notifyWakeLockListener
where some required logic was put behind a feature flag.

Bug: 296508214
Test: atest NotifierTest
Change-Id: Id69ecb9c2cd90ee5342783ea1b220c8290212e81