Add setTime and setTimeZone API.

Fix: 67497358
Test: wait for cts test in the following cl. For unitest:
 runtest -x services/tests/servicestests/src/com/android/server/devicepolicy/DevicePolicyManagerTest.java

Add setTime and setTimeZone API in devicepolicymanager.
Add unitest for each API.
Following design doc: https://docs.google.com/document/d/1NV93mr2CT157S_haru1QbKo9HLeP9iPM9eMiGfVmfCM/edit

Change-Id: I188c27b0b99137b6f01e42ae1ad49356ce0a81b2