TUN-4456: Replaced instances of Tick() with Ticker() in h2mux paths

time.Tick() does not get garbage collected because the channel
underneath never gets deleted and the underlying Ticker can never be
recovered by the garbage collector. We replace this with NewTicker() to
avoid this.

h2mux/muxreader.go

@@ -69,12 +69,13 @@ func (r *MuxReader) run(log *zerolog.Logger) error {
 
 	// routine to periodically update bytesRead
 	go func() {
-		tickC := time.Tick(updateFreq)
+		ticker := time.NewTicker(updateFreq)
+		defer ticker.Stop()
 		for {
 			select {
 			case <-r.abortChan:
 				return
-			case <-tickC:
+			case <-ticker.C:
 				r.metricsUpdater.updateInBoundBytes(r.bytesRead.Count())
 			}
 		}