http: use the IDN decoded name in HSTS checks

Otherwise it stores the info HSTS into the persistent cache for the IDN
name which will not match when the HSTS status is later checked for
using the decoded name.

Reported-by: Hiroki Kurosawa

Closes #10111

lib/http.c

@@ -3646,7 +3646,7 @@ CURLcode Curl_http_header(struct Curl_easy *data, struct connectdata *conn,
 #endif
             )) {
     CURLcode check =
-      Curl_hsts_parse(data->hsts, data->state.up.hostname,
+      Curl_hsts_parse(data->hsts, conn->host.name,
                       headp + strlen("Strict-Transport-Security:"));
     if(check)
       infof(data, "Illegal STS header skipped");