Adds support for asynchronous "raw" DNS API for clients.
API allows apps to use multinetworking capability correctly
and also allows other query types than A/AAAA.
Test: built, flashed, booted
cts test: NativeDnsAsyncTest
Change-Id: I4701b76bd8f0094ef1bdd7c5371b54387914a91b
Being able to update this handle is necessary to ensure that
system-only OTAs do not break vendor code that relies on
nethandles.
Bug: 63052780
Test: walleye builds, boots, networking works
Test: MultinetworkApiTest CTS tests passes
Change-Id: I049a4ad2610ca68b8f56377b63be7e5e8ce76039