+ Convert tests to use Junit4
+ Add annotations to specify required conditions for the test to run.
Bug: 137859686
Test: atest hostsidetests/net/src/com/android/cts/net/HostsideRestrictBackgroundNetworkTests.java
Test: atest hostsidetests/net/src/com/android/cts/net/HostsideNetworkCallbackTests.java
Change-Id: I93317c201a0ea06732e29154ab7e140735381f59