[go/timer] eliminate time.After
[go/timer] eliminate time.After

Timer from time.After is not recyclable and not only takes place
in timers heap if unused, but also will spawn additional unnecessary goroutine.

Signed-off-by: Alexander Morozov <2043cda4df124b840b98ee1c4307c199042efdf7@gmail.com>

mahak/vitess,enisoc/vitess,HubSpot/vitess,enisoc/vitess,HubSpot/vitess,davygeek/vitess,enisoc/vitess,davygeek/vitess,HubSpot/vitess,dcadevil/vitess,dcadevil/vitess,tinyspeck/vitess,tinyspeck/vitess,tinyspeck/vitess,HubSpot/vitess,HubSpot/vitess,HubSpot/vitess,vitessio/vitess,davygeek/vitess,vitessio/vitess,dcadevil/vitess,tinyspeck/vitess,HubSpot/vitess,enisoc/vitess,mahak/vitess,vitessio/vitess,tinyspeck/vitess,vitessio/vitess,vitessio/vitess,mahak/vitess,enisoc/vitess,davygeek/vitess,mahak/vitess,enisoc/vitess,tinyspeck/vitess,mahak/vitess,vitessio/vitess,davygeek/vitess,vitessio/vitess,tinyspeck/vitess,mahak/vitess,dcadevil/vitess,dcadevil/vitess,HubSpot/vitess,enisoc/vitess,dcadevil/vitess,dcadevil/vitess,davygeek/vitess,davygeek/vitess,mahak/vitess,mahak/vitess,vitessio/vitess