Transport needs to be a selector when looking for an existing dispatch.

The specific TCP/TLS/HTTPS transports parameters need to be matched when selecting a dispatch. dispatch.c is currently missing this capability.

This is brought about because !9407 (merged) was failing because it attempted to using and existing TCP socket with paying attention to the transport. The test there was expecting both TLS failures and successes when talking to the same TCP end point using different transport and it was failing non-deterministically depending whether the TCP connection was being reused or not and the actual transport parameters.