Fix fetchBody with a retry

There seems to be a race condition with chrome and CDP requests when
trying to retrieve the response body. If the call to retrieve the
response body is too "quick", then we get an error back.

However with retries and a sleep it seems to solve the issue with the
small tests i have performed. I suspect this will be a greater issue in
the wild.

internal/js/modules/k6/browser/common/http.go

@@ -488,7 +488,27 @@ func (r *Response) fetchBody() error {
 		return nil
 	}
 	action := network.GetResponseBody(r.request.requestID)
-	body, err := action.Do(cdp.WithExecutor(r.ctx, r.request.frame.manager.session))
+
+	// Try to fetch the response body. If the request to retrieve the response
+	// body is too "quick" then the response body is not available. After
+	// retrying we have a better chance of getting the response body.
+	var body []byte
+	var err error
+	maxRetries := 5
+	for i := 0; i <= maxRetries; i++ {
+		body, err = action.Do(cdp.WithExecutor(r.ctx, r.request.frame.manager.session))
+		if err == nil {
+			break
+		}
+		if strings.Contains(err.Error(), "No data found for resource with given identifier") {
+			if i == maxRetries {
+				break
+			}
+			time.Sleep(100 * time.Millisecond)
+			continue
+		}
+		break
+	}
 	if err != nil {
 		return fmt.Errorf("fetching response body: %w", err)
 	}