Add more tests for NitzStateMachine

This test-only change contains a large refactoring to
make it easier to write tests.

More tests are included so there is now coverage of
countries that have multiple zones and countries that
have one zone, with different orders of information
becoming available.

Bug: 63743683
Test: atest FrameworksTelephonyTests
Change-Id: I7aecb26027cb5bb7b26a5081cf051ad1ee76d84e