Make ConnectionFileDescription work with all sockets

Summary:
My main goal here is to make lldb-server work with Android Studio.

This is currently not the case because lldb-server is started in platform mode listening on a domain socket. When Android Studio connects to it lldb-server crashes because even though it's listening on a domain socket as soon as it gets a connection it asserts that it's a TCP connection, which will obviously fails for any non-tcp connection.

To do this I came up with a new method called GetConnectURI() in Socket that returns the URI needed to connect to the connected portion of the socket.

Reviewers: labath, clayborg, xiaobai

Reviewed By: labath

Subscribers: mgorny, jfb, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D62089

llvm-svn: 362173