Revert "ui.backend.cocoa.views: call super.prepareOpenGL()."
Revert "ui.backend.cocoa.views: call super.prepareOpenGL()."

This reverts commit 864912f446f173eca3cd1dc8154121eb6d119fe6.

This patch breaks the UI on 10.13

factor/factor,mrjbq7/factor,tgunr/factor,mrjbq7/factor,AlexIljin/factor,bpollack/factor,bpollack/factor,tgunr/factor,bpollack/factor,bpollack/factor,AlexIljin/factor,factor/factor,bpollack/factor,mrjbq7/factor,factor/factor,mrjbq7/factor,factor/factor,mrjbq7/factor,factor/factor,AlexIljin/factor,tgunr/factor,AlexIljin/factor,mrjbq7/factor,AlexIljin/factor,tgunr/factor,AlexIljin/factor,factor/factor,bpollack/factor,bpollack/factor,AlexIljin/factor,tgunr/factor,tgunr/factor