The API is the getter couterpart for setprocnetwork.
Use it in NetworkUtils so that the NDK API can be the source of truth
for the process network.
Bug: 171540887
Test: atest CtsNetTestCases
Tests in change I311b58585033c2ca50ce5477ea9cd94b6f127507
Change-Id: Ie8f68cf1fa57deddb63324c1abf3d6fd5b0ef500
Use the jniThrowErrnoException that is available in JNIHelp, instead of
reimplementing in NetworkUtils.
Bug: 179229316
Test: device boots and has connectivity
Change-Id: I257a9d55ce1f5a7c588e209b4a89d3e7a3e09994
Keep the utilities included via a library, but move them out of
core/jni, and prepare a library to package them together with
framework-connectivity.
Also remove unnecessary dependencies in framework-connectivity.
Bug: 171540887
Test: device boots and has connectivity
Change-Id: I0b55dfe92f3cb6e848d79ac7953756f39aaa2597
