Run loopback tests with network thread.

Running with a network thread provides a more realistic simulation. Like
a real network, packets are handed off to a socket, or buffer, and then
the call returns. This prevents weird scenarios when both the sending
side and receiving side are on the call stack simultaneously, which can
cause deadlocks as locks could otherwise be taken simultaneously in both
the sender and receiver order by the same thread.

BUG=
R=stefan@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/2000005

git-svn-id: http://webrtc.googlecode.com/svn/trunk@4522 4adac7df-926f-26a2-2b94-8c16560cd09d
6 files changed