Hyperfoil might fire an additional user

[lampajr]

As discovered here #357 (comment) Hyperfoil with the following configuration (this actually might happen in other configs but with this one, it is much more visible)

• constantRate
• no variance

might generate an additional fire (user) at the end of the phase.

This looks happening when the last fire time is scheduled to happen exactly at the end of the phase duration:

11:34:52,900 TRACE  (epollEventLoopGroup-3-1) [i.h.c.i.PhaseInstanceImpl] fetchIndex: 10000 after start, 41 started (0 throttled), next user in 250 ms, scheduling decisions tooks 0 ms

This ends up in having expected number of requests + 1, e.g., 41 instead of 40.