DEBUG: stream: Report lra/fsb values for front end back SC in stream dump

DEBUG: stream: Report lra/fsb values for front end back SC in stream dump

REX and WEX date are already reported. But if the corresponding SC cannot
expire on read or write, "<NEVER>" is reported instead. The same is reported
if no expiration date is set. It is not really convenient because we cannot
distinguish the two cases.

So, now, for each SC, read and wirte timer (rto/wto) are also reported in
the dump, based on .lra/.fsb dates and the current I/O timeout. The SC I/O
timeout is also reported.