Run modernize (#21546)

`go run golang.org/x/tools/gopls/internal/analysis/modernize/cmd/modernize@latest -fix -test ./...` executed.

`go generate ./...` ran afterwards to keep generated.

cmd/perf-tests.go

@@ -375,7 +375,7 @@ func siteNetperf(ctx context.Context, duration time.Duration) madmin.SiteNetPerf
 		}
 		info := info
 		wg.Add(connectionsPerPeer)
-		for i := 0; i < connectionsPerPeer; i++ {
+		for range connectionsPerPeer {
 			go func() {
 				defer wg.Done()
 				ctx, cancel := context.WithTimeout(ctx, duration+10*time.Second)