Fix error handling in tests file

If the errgroup fail (e.g. the writer crash), also stop the deadlineCtx
which will cause program to stop.
Without this, writers will stop and the program will hang.

tests/remote-storage-bench/main.go

@@ -91,16 +91,24 @@ func run(deadlineCtx context.Context) error {
 		})
 	}
 
-	ctx := context.Background()
+	group, ctx := errgroup.WithContext(context.Background())
 
 	if *runDuration > 0 {
 		var cancel context.CancelFunc
 
 		deadlineCtx, cancel = context.WithTimeout(deadlineCtx, *runDuration)
 		defer cancel()
+
+		go func() {
+			// If the errgroup context is stopped, stop the deadlineCtx.
+			// deadlineCtx is used for work generation.
+			// ctx (errgroup context) is used for writers.
+			// We use two context, because work generation need to be stopped before writers
+			<-ctx.Done()
+			cancel()
+		}()
 	}
 
-	group, ctx := errgroup.WithContext(ctx)
 	workChannel := make(chan prompb.WriteRequest, 10)
 
 	for _, writer := range writers {