LibPDF: Fix paths with negatively sized re (rect) commands

Turns out the width/height in a `re` command can be negative. This
results in rectangles with different winding orders. For example, a
negative width results in a reversed winding order.

Previously, this was lost by passing the rect through an
`AffineTransform` before constructing the path. So instead, this
constructs the rect path, and then transforms the resulting path.

Userland/Libraries/LibPDF/Renderer.h

@@ -155,6 +155,8 @@ private:
     template<typename T>
     ALWAYS_INLINE Gfx::Rect<T> map(Gfx::Rect<T>) const;
 
+    Gfx::Path map(Gfx::Path const&) const;
+
     Gfx::AffineTransform calculate_image_space_transformation(int width, int height);
 
     PDFErrorOr<NonnullRefPtr<PDFFont>> get_font(FontCacheKey const&);