Create service-connectivity.jar

Create a new target service-connectivity to split
ConnectivityService from services.core.

Add ConnectivityServiceInitializer for initializing
ConnectivityService and add systemReady() in
ConnectivityManager so that SystemServer can call systemReady()
through ConnectivityManager which won't change current behavior.

Bug: 158268939
Test: make target-java, make host-java
      atest FrameworksNetIntegrationTests
      atest FrameworksNetTests
      make, device can boot,
      atest CtsStrictJavaPackagesTestCases
      wifi and mobile data work.
Change-Id: Ie732bfaf381404af0bb599ca2f421a96e7aa4257

tests/net/Android.bp

@@ -59,6 +59,7 @@ android_test {
         "mockito-target-minus-junit4",
         "net-tests-utils",
         "platform-test-annotations",
+        "service-connectivity",
         "services.core",
         "services.net",
     ],

tests/net/integration/src/com/android/server/net/integrationtests/ConnectivityServiceIntegrationTest.kt

@@ -167,7 +167,7 @@ class ConnectivityServiceIntegrationTest {
         cm = ConnectivityManager(context, service)
         context.addMockSystemService(Context.CONNECTIVITY_SERVICE, cm)
 
-        service.systemReady()
+        service.systemReadyInternal()
     }
 
     private inner class TestConnectivityService(deps: Dependencies) : ConnectivityService(

tests/net/java/com/android/server/ConnectivityServiceTest.java

@@ -1246,7 +1246,7 @@ public class ConnectivityServiceTest {
         // Create local CM before sending system ready so that we can answer
         // getSystemService() correctly.
         mCm = new WrappedConnectivityManager(InstrumentationRegistry.getContext(), mService);
-        mService.systemReady();
+        mService.systemReadyInternal();
         mockVpn(Process.myUid());
         mCm.bindProcessToNetwork(null);