Make tests compatible with mockito-extended

This does not change the mockito library to use mockito-extended in
FrameworksNetTests, but changes the tests so that they would pass if
built against that library.

This is useful to run FrameworksNetTests in a common test suite with
other tests that use mockito-extended, for example a common connectivity
coverage test target.

The change includes increasing the test timeout in
ConnectivityServiceTest, as mockito-extended can have performance impact
(~3 times on hwasan builds). This change does not make tests run slower
in the current FrameworksNetTests suite though.

Bug: 187935317
Test: atest FrameworksNetTests
Original-Change: https://android-review.googlesource.com/1737400
Merged-In: I61fa371e8957037075a2617a014647ff062207c6
Change-Id: I61fa371e8957037075a2617a014647ff062207c6