Implement INetworkMonitorCallbacks#notifyNetworkTestedWithExtras.

INetworkMonitorCallbacks defines notifyNetworkTestedWithExtras() for
notifying ConnectivityService of networks being tested along with a
PersistableBundle of extras. A new event is introduced for
NetworkStateTrackerHandler to notify the ConnectivityDiagnosticsHandler
before continuing with the normal processing for "network tested"
notifications. The event is also used in the
ConnectivityDiagnosticsHandler.

Bug: 143187964
Bug: 147391402
Test: compiles.
Test: atest CtsNetTestCases FrameworksNetTests
Change-Id: Iab29da790c0f5faae68227770bc3a84bbc94f124
Merged-In: Iab29da790c0f5faae68227770bc3a84bbc94f124