reduce unnecessary logging during speedtest (#14387)

- speedtest logs calls that were canceled
  spuriously, in situations where it should
  be ignored.

- all errors of interest are always sent back
  to the client there is no need to log them
  on the server console.

- PUT failures should negate the increments
  such that GET is not attempted on unsuccessful
  calls.

- do not attempt MRF on speedtest objects.

cmd/object-api-errors.go

@@ -31,6 +31,9 @@ func toObjectErr(err error, params ...string) error {
 	if err == nil {
 		return nil
 	}
+	if errors.Is(err, context.Canceled) {
+		return context.Canceled
+	}
 	switch err.Error() {
 	case errVolumeNotFound.Error():
 		apiErr := BucketNotFound{}