SVG export doesn't support boolean shape operators anymore

[phlntn]

This seems to be a regression in the new SVGOMG export module.

Here's the source file. Each shape is made out of two rectangles with varying boolean modes (add, subtract, exclude, intersect).

This is what Generator exports by default:

Setting "svgomg-enabled": false in the Generator config produces the correct output:

I realize that merging the shapes fixes the output, but that is not an acceptable solution.