Rotation in the mmark example leads to tile-sized artifacts

[DJMcNab]

Zulip thread: #gpu > Artifacts in rotated mmark example

OS: Fedora Linux 39
CPU/GPU: Intel i5-1240p (integrated Graphics)
API: Vulkan

Also reported in the Zulip thread to occur on different machines (probably macs?), so doesn't seem to be API specific

There are several 16x16 pixel solid blocks, along with several axis-aligned right-angled triangles in unexpected places when the mmark example is rotated.

Screenshot (from the GPU renderer)

To reproduce:

cargo run -p with_winit -- --test-scenes

then press ← once, then Q (or E) a few times to see the artifacts.

edit: Removed a section on the CPU renderer, as I'm not sure how I reproduced that

[DJMcNab]

This was resolved by #440, which integrated linebender/kurbo#325 and linebender/kurbo#326