poppler: cairo: Don't override the antialias settings from the cairo_t
This partially reverts commit 853e9499, which made CairoOutputDev store the antialias setting, and applying it to its cairo context.
Instead, just copy the antialias (and font antialias) setting from the passed cairo context to newly created contexts. That way, the application can control the antialias settings.
Use this in pdftocairo to implement its -antialias option.