Build service-connectivity with system_server API

As all dependencies on hidden API have been removed, build
service-connectivity against system_server_current.

Bug: 171540887
Test: device boots, has connectivity
Merged-In: I454e8a0a8d0e0f9e6d21a8e8faf5a9e299962ad4
Change-Id: I87ef0968c96272c99c787fdbc21db261acdea6aa

services/net/Android.bp

@@ -83,3 +83,15 @@ filegroup {
         "//packages/modules/Connectivity/Tethering"
     ],
 }
+
+filegroup {
+    name: "services-connectivity-shared-srcs",
+    srcs: [
+        // TODO: move to networkstack-client
+        "java/android/net/IpMemoryStore.java",
+        "java/android/net/NetworkMonitorManager.java",
+        // TODO: move to libs/net
+        "java/android/net/util/KeepalivePacketDataUtil.java",
+        "java/android/net/util/NetworkConstants.java",
+    ],
+}