JDK-8163921 changed the default Accept header in HTTP client. This looked to be an innocious change on a surface, but it apparently breaks applications. We are seeing internal reports where services started to receive differently-typed responses, now that we do not prefer `text/html, image/gif, image/jpeg` anymore.

Arguably, changing the Accept header to `*/*` is a good move, since it drops a preference JDK's HTTP client should not really have. But the breakages show this should only be done in major releases, so users can catch the bugs and set their Accept headers properly. We should not be doing this policy change in an update release.