connection: terminate after goaway

connection: terminate after goaway

When a multiplex connection (h2/h3) is shutdown by the server, the
reported number of parallel transfers allowed drops to 0.

Determine that when the last transfer is done and terminate the
connection instead of keeping it in the cache.

We detect the drop to 0 also when we try to reuse such a connection, but
if we know this at the time the last transfer is done, we better
terminate it right away.

Have a consistent trace logging to this with the connections current
hostname and port. Adjust test expectations to carry port numbers.

Closes #17884