Don't mesh a polygon in CairoMakie

[jaakkor2]

CairoMakie plot of a polygon is a mesh resulting in a raster .svg file

Fixes #2396

Treat a polygon same way as an array of polygons

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist

• Added unit tests for new algorithms, conversion methods, etc.

[jkrumbiegel]

Would be great if you could add a plot with a couple different poly versions (including your new one) to this file to ensure they don't get rasterized again in the future. You can make a new testset for them

https://github.com/MakieOrg/Makie.jl/blob/master/CairoMakie/test/rasterization_tests.jl

[jaakkor2]

Thank you @jkrumbiegel for pointing out the location of the rasterization tests. I now simply added a simplest polygon to the existing testset.

[fatteneder]

This PR broke the 'polygon with hole' example #2456

[jkrumbiegel]

Ah damn it seemed not to have a visual regression test. It shouldn't be too hard to fix, sometimes holes don't work right if the interiors are not the opposite winding order, which they should have but don't always have. Not sure what the problem was exactly in the docs case.