Use "raw" syscalls in NetworkInterface.

Libcore.os offers a bunch of nice checks/guards, but sometimes they
can be too aggressive, such as requiring that all network sockets be
tagged, even when code in NetworkInterface knows that its sockets
will never be used to send/receive data.

To avoid these false-positive warnings, add new "rawOs" field and
switch some NetworkInterface calls over to using it.

Test: builds, boots, no longer seeing tagging warnings
Bug: 34610007
Change-Id: I13c12fb7221ede4712f8faa82c627d966083d9d1
2 files changed