[Impeller] Rasterizer::ScreenshotLayerTreeAsImage uses Skia rendering when running with Impeller. #135052
Description
Only part of the screen seems to be captured on Wonderous. On iOS 17 the native screenshot tool is broken so we're falling back to rasterizer screenshots. These aren't setting up an aiks context, so its rendering skia but no images.
Expected:
Actual:
