Backport some helpers in ConnectivityServiceTest.

These were added in aosp/1527378, which is impractical to
backport.

Bug: 172870110
Test: test-only change
Change-Id: Id3d12b23034b284c8f7dffb5167244e1e43987e2
Merged-In: I827543751dbf5e626a24ec02cd6f50b423f5f761
(cherry picked from commit 4c36cb764a6ffbc81acdbf2297cde010a7396f8b)
1 file changed