Fixed that locale tracker incorrectly used the invalid cell info

Fixed that the locale tracker used the invalid cached cell info
when airplane mode is turned on. We should clear the cache when
airplane mode is on.

The previous fix ag/4058309 was reverted because it caused crash.
This is the right fix with unit tests added.

Test: Manual
Bug: 79230575, 79861643, 79771106
Change-Id: I410c309a6afa42d98299819675afa8c3de151215