Combine tcp_connect and socket_spec_connect.

This will make it easier to add new types of transports by combining the
logic the adb server and adb daemon use to connect to things.

Bug:121166534
Test: adb connect against a cuttlefish instance over the shm proxy.
Change-Id: Ic7fc848c60a85eef968c3735838c87cb7fdaf38b
6 files changed