Import net utils from com.android.net.module.util

This imports the jarjared version of net-utils-framework-common.

Eventually these classes will be moved to com.android.net.module.util in
source (not with jarjar), and the jarjar rules will be moved to each
user of the shared library as:

com.android.net.module.util.** com.android.net.[modulename].util.@1

This should avoid problems with having each user of the shared library
apply jarjar rules to android.net.util, which also contains classes that
are not part of the shared library (such as TetheringUtils).

Test: atest FrameworksTelephonyTests
Bug: 138306002
Change-Id: Ic4ee5ac891a5c724c89163eae869c54432f6b4a7