MEDIUM: h2: produce some logs on early errors that prevent streams from being created

MEDIUM: h2: produce some logs on early errors that prevent streams from being created

The h2 mux currently lacks some basic transparency. Some errors cause the
connection to be aborted but they couldn't be reported. With this patch,
almost all situations where an error will cause a stream or connection to
be aborted without the ability for an existing stream to report it will be
reported in the logs. This at least provides a solution to monitor the
activity and abnormal traffic.