Revert "LibWeb: Fix clip of hidden overflow..."

This reverts commit eb1ef59603c13c43b87c099c43c4d118dc8441f6.

The idea of saving clip box to apply it to handle `overflow: hidden`
turned out to break painting if box is painted before it's containing
block (it is possible if box has negative z-index).

Userland/Libraries/LibGfx/Painter.h

@@ -177,7 +177,6 @@ public:
     }
 
     IntRect clip_rect() const { return state().clip_rect; }
-    void set_clip_rect(IntRect const&);
 
     int scale() const { return state().scale; }