Modified local spawning in debugserver processes to use a new --reverse-connect option so that debugserver actually connects back to LLDB instead of LLDB connecting to debugserver.

This gets rid of our hacky "get_random_port()" which would grab a random port and tell debugserver to open that port. Now LLDB creates, binds, listens and accepts a connection by binding to port zero and sending the correctly bound port down as the host:port to connect back to.

Fixed the "ConnectionFileDescriptor" to be able to correctly listen for connections from a specified host, localhost, or any host. Prior to this fix "listen://" only accepted the following format:

listen://<port>

But now it can accept:

listen://<port>         // Listen for connection from localhost on port <port>
listen://<host>:<port>  // Listen for connection from <host> and <port>
listen://*:<port>       // Listen for connection from any host on port <port>