Refs #9896
Found by @eliransin. Call to new_segment was wrapped in with_timeout.
This means that if primary caller timed out, we would leave new_segment
calls running, but potentially issue new ones for next caller.
This could lead to reserve segment queue being read simultanously. And
it is not what we want.
Change to always use the shared_future wait, all callers, and clear it
only on result (exception or segment)
Closes#10001
(cherry picked from commit 445e1d3e41)
61db571a44