Domain socket path for autest should be in the trafficserver runtime directory, not the test directory

[cmcfarlen]

Currently, the UDS path is configured to use the test directory. If traffic_server changes user id and deescalates privilege, then it will not have access to write to the currently configured path for the server domain socket. Also, if an autest configure multiple traffic servers, the current path will conflict.

I recommend moving the configured UDS path to be the trafficserver runtime directory.