Apache HttpClient 5.1 doesn't cope with Jetty 10 sending
SETTINGS_ENABLE_CONNECT_PROTOCOL in the settings frame. It also appears
to be unstable when using Undertow, resulting in a failure and
"UT005032: Listener not making progress on framed channel, closing
channel to prevent infinite loop" being logged on the server-side.
Local experimentation suggests that Jetty's HTTP/2 client is more
robust and that it does not trigger the problem with Undertow. It also
fixes the problem with SETTINGS_ENABLE_CONNECT_PROTOCOL when testing
against Jetty 10 so this commit updates the tests to use Jetty's client.
Closes gh-26040
5873dddc1c