Remove special handling of wakeup alarm for car

- Android does not guarantee wakeup from wake up alarm in special power
  state like deep sleep, deep doze and etc.
- Car devices will still not support wakeup while car is in deep sleep but
  that enforcement is done in kernel level, not AlarmManagerService.
- This effectively reverts commit c32088c1 but
  is keeping generic test added with that CL.

Bug: 123430582
Test: Run the unit test.

Change-Id: If951e10b1c1a0fcafaa1c44990f9c7117ba8973d