ConnectivityService: Sort requests and networks in dumpsys.

This patch adds two utility functions for sorting requests and networks
tracked by ConnectivityService by request id and network id
respectively.

These utility functions are then used to improve the output of
adb shell dumpsys connectivity so that networks and requests are
printed in a more stable fashion.

Bug: none
Test: Compiled, flashed, booted, checked output of adb shell
      dumpsys connectivity.

Change-Id: I3cb9b2ceab64145611a416dcb8c5d512838a2626