Remove vargs check as arg order switched to match client Page

[craigbeck]

Unifying the Page.render and PageForServer.render args resulted in changing arg order so status is last optional arg.

This removes the now incorrect var ags handling for PageForServer.render

[ericyhwang]

We should look into adding at least a basic server-render test, to catch future regressions that only affect the server-render path but not the client-render path.