all: use AbsTime.Add instead of conversion (#25417)

common/mclock/simclock.go

@@ -58,7 +58,7 @@ func (s *Simulated) Run(d time.Duration) {
 	s.mu.Lock()
 	s.init()
 
-	end := s.now + AbsTime(d)
+	end := s.now.Add(d)
 	var do []func()
 	for len(s.scheduled) > 0 && s.scheduled[0].at <= end {
 		ev := heap.Pop(&s.scheduled).(*simTimer)
@@ -134,7 +134,7 @@ func (s *Simulated) AfterFunc(d time.Duration, fn func()) Timer {
 func (s *Simulated) schedule(d time.Duration, fn func()) *simTimer {
 	s.init()
 
-	at := s.now + AbsTime(d)
+	at := s.now.Add(d)
 	ev := &simTimer{do: fn, at: at, s: s}
 	heap.Push(&s.scheduled, ev)
 	s.cond.Broadcast()