Testconfig: Replace iOS 10.8 stage with 10.9 stage

There is no need to run iOS stage on OSX 10.8 and 10.9. Removing
all OSX 10.8 iOS stages.

Change-Id: I1a9bf509b264982f032c520396a1255445af37f6
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@digia.com>
Reviewed-by: Tony Sarajärvi <tony.sarajarvi@digia.com>