Testconfig: Sanitizing QtWebKit's CI stages

Disabled IOS stage, while QtWebkit can't be built for it.
QtWebKit's multimedia is not supported in wince.

Change-Id: I8f9ce46b165bc257fc5a38c9f64e54b38e601f0d
Reviewed-by: Michael Bruning <michael.bruning@digia.com>
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@digia.com>