Move Inet[4]AddressUtils to libs/net

The classes should not be picked up from frameworks/base, as they are
part of several mainline modules.

Also refine comments in DhcpResults following feedback in previous
change.

Bug: 151052811
Test: m; manual: flashed, wifi and telephony working
Test: atest NetworkStackCoverageTests
Change-Id: I7074651c6a2a7a6b11bcf13cc4bb03833d7d655f
diff --git a/Tethering/src/android/net/dhcp/DhcpServingParamsParcelExt.java b/Tethering/src/android/net/dhcp/DhcpServingParamsParcelExt.java
index 4710a30..aaaec17 100644
--- a/Tethering/src/android/net/dhcp/DhcpServingParamsParcelExt.java
+++ b/Tethering/src/android/net/dhcp/DhcpServingParamsParcelExt.java
@@ -16,7 +16,7 @@
 
 package android.net.dhcp;
 
-import static android.net.shared.Inet4AddressUtils.inet4AddressToIntHTH;
+import static com.android.net.module.util.Inet4AddressUtils.inet4AddressToIntHTH;
 
 import android.net.LinkAddress;
 import android.util.ArraySet;
diff --git a/Tethering/src/android/net/ip/IpServer.java b/Tethering/src/android/net/ip/IpServer.java
index 1671dda..5239947 100644
--- a/Tethering/src/android/net/ip/IpServer.java
+++ b/Tethering/src/android/net/ip/IpServer.java
@@ -19,13 +19,14 @@
 import static android.net.RouteInfo.RTN_UNICAST;
 import static android.net.TetheringManager.TetheringRequest.checkStaticAddressConfiguration;
 import static android.net.dhcp.IDhcpServer.STATUS_SUCCESS;
-import static android.net.shared.Inet4AddressUtils.intToInet4AddressHTH;
 import static android.net.util.NetworkConstants.RFC7421_PREFIX_LENGTH;
 import static android.net.util.NetworkConstants.asByte;
 import static android.net.util.PrefixUtils.asIpPrefix;
 import static android.net.util.TetheringMessageBase.BASE_IPSERVER;
 import static android.system.OsConstants.RT_SCOPE_UNIVERSE;
 
+import static com.android.net.module.util.Inet4AddressUtils.intToInet4AddressHTH;
+
 import android.net.INetd;
 import android.net.INetworkStackStatusCallback;
 import android.net.IpPrefix;