In non-foreground gc mode, if no victim is selected, the gc process
will wait for no_gc_sleep_time before waking up again. In this
subsequent time, even though a victim will be selected, the gc process
still waits for no_gc_sleep_time before waking up. The configuration
of wait_ms is not reasonable.
After any of the victims have been selected, we need to reset wait_ms to
default sleep time from no_gc_sleep_time.
Signed-off-by: Yuwei Guan <Yuwei.Guan@xxxxxxxxxxxxx>