GtkGLArea: Always destroy context on unrealize
GtkGLArea: Always destroy context on unrealize

We had some code that tried to reuse the context over realize, but
that doesn't work as we need to share with the possibly new
paint context of the re-realized window.

Lyude/gtk-,Lyude/gtk-,jigpu/gtk,davidgumberg/gtk,davidgumberg/gtk,jigpu/gtk,Adamovskiy/gtk,alexlarsson/gtk,Lyude/gtk-,ahodesuka/gtk,Adamovskiy/gtk,alexlarsson/gtk,jadahl/gtk,Adamovskiy/gtk,grubersjoe/adwaita,chergert/gtk,ahodesuka/gtk,jigpu/gtk,chergert/gtk,chergert/gtk,grubersjoe/adwaita,ahodesuka/gtk,Lyude/gtk-,Lyude/gtk-,grubersjoe/adwaita,jigpu/gtk,chergert/gtk,alexlarsson/gtk,alexlarsson/gtk,jigpu/gtk,Lyude/gtk-,jadahl/gtk,grubersjoe/adwaita,jadahl/gtk,chergert/gtk,alexlarsson/gtk,Lyude/gtk-,grubersjoe/adwaita,davidgumberg/gtk,ahodesuka/gtk,jigpu/gtk,Adamovskiy/gtk,grubersjoe/adwaita,grubersjoe/adwaita,ahodesuka/gtk,jadahl/gtk,jadahl/gtk,Adamovskiy/gtk,ahodesuka/gtk,Adamovskiy/gtk,davidgumberg/gtk,alexlarsson/gtk,alexlarsson/gtk,davidgumberg/gtk,Adamovskiy/gtk,ahodesuka/gtk,Lyude/gtk-,grubersjoe/adwaita,Adamovskiy/gtk,jadahl/gtk,davidgumberg/gtk,jigpu/gtk,jadahl/gtk,chergert/gtk,ahodesuka/gtk,chergert/gtk,davidgumberg/gtk,chergert/gtk,jigpu/gtk,alexlarsson/gtk,jadahl/gtk,davidgumberg/gtk