Tests emulation of User-Agent header string when the request is redirected.
Navigate to redirect.php
User-Agent: ua-set-by-devtools
Accept-Language: ko, en;q=0.9
Fetch redirect.php
User-Agent: ua-set-by-devtools
Accept-Language: ko, en;q=0.9
XHR redirect.php
User-Agent: ua-set-by-devtools
Accept-Language: ko, en;q=0.9