DrawOperation inflates bounds by Pen Thickness (needs moving)

[danwalmsley]

https://github.com/AvaloniaUI/Avalonia/blob/master/src/Avalonia.Visuals/Rendering/SceneGraph/DrawOperation.cs#L14

This inflate call assumes that pen thickness may not have already been taken into account, some of the operations like GeomeryNode let skia tell us the bounds and it seems this will be inflating them when it isnt necessary.