[SP26.1] Add assert function for parceling NetworkStats

In ParcelUtils there are methods that help to verify parceling
correctness. However, they can only be applied to objects which
implement equals.

For NetworkStats, equals are not overrided due to performace
might be impacted if everyone use it. Hence specfic function
to verify parceling correectness is needed.

Test: atest NetworkStatsApiTest NetworkStackTests
Bug: 150644692
Change-Id: I48aa73117bc7db981ffaef5365f96e46d431bd6e