Fix case for not reverting country code on cellular loss

This CL allows us to keep using last known country code
on cellular loss and |mRevertCountryCodeOnCellularLoss| is
set to false.

This also fixes simCardRemoved() to revert country code
unconditionally, and cleans up code for airplaneModeEnabled().

Bug: 65602314
Test: compile, unit tests
Change-Id: I7b15d9ae197c5e2aacd7788b505e386f970786ed
2 files changed