Make sure tests know to handle both early creation true and false

This is necessary to pass tests whatever the values of the features are.

NetworkAgentTest was updated assuming the feature was true, so
this patch revives the old code for when it's false.

TestableNetworkAgent reads the feature directly from
ConnectivityManager when it's not mocked.

Test: CtsNetTestCases
Change-Id: Ia556fbb1d1b6a38a4995b021981e2693d778bfff
3 files changed