Add Os.connect(fd, SocketAddress) to public API

1. There are already related socket API methods that return
   SocketAddress, such as Os.getpeername().
2. Having APIs that take SocketAddress are a closer match
   to the POSIX APIs that android.system.Os is exposing,
   and are more flexible than just taking InetAddress+port
   combinations since the latter only supports IPv4 and
   IPv6.

This was covered by tests in change:
Iadf9f10e26bbc650c5e1b9d03f32c5dafb6f21b4

And completes Ic496c1212dc2d97cf34db2a7c7d024b02790e8ed.

Test: m
Bug: 123062477
Change-Id: I885bfe1bf24a361bef2bb2f783622b934637ba99