Remove usage of hidden NetworkUtils from Formatter

Use the Inet4AddressUtils common utility instead.
NetworkUtils is moving to the connectivity module, so its hidden symbols
are not accessible from the framework. Use the Inet4AddressUtils utility
instead.

NetworkUtils.intToInetAddress is also deprecated.

Bug: 174436414
Test: m

Change-Id: Ia4f4de2f23b2e2be056f78cc30259814f9a4dc91