Fixed LocaleTracker behaviors

1. Decouple network country code with SIM country code. This makes
   TelephonyManager.getNetworkCountryIso() behave as the description
   on the API documents. getNetworkCountryIso() returns the country
   codecurrent derived from the registered cell or nearby cell's
   MCC.
2. Fixed a bug that when device is on airplane mode with wifi calling
   available, service state was actually overridden to IN_SERVICE.

Fix: 179849551
Test: Manual
Change-Id: Ie3ec6768ffe924dd0be3e91a64dac32dacebe50b