Run NetworkStackIntegrationTest with Parameterized.class.

The flag of parsing netlink event brings two different codepath, when
it's disabled NetworkObserver is still used in the integration test,
otherwise, new codepath which processes netlink message in upper layer
will be used instead.

To cover both above cases in the integration test, make test run with
Parameterized.class, that iterates each test method with the pre-defined
parameterized boolean flag value.

Bug: 163492391
Test: atest NetworkStackIntegrationTests
Change-Id: Id0f6db887794c8e172e43bc4b093c3951ae27d00