Only convert domain name to ASCII

IDNA is about domain name only, so ignore username, password and port.

Fixes #10010.
2 jobs for valid_url in 7 minutes and 45 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Test
passed #21428
code-quality

00:05:34

3.0%
 
  Build
passed #21429
linux

00:02:10