A page whose MediaBox has a non-zero origin (e.g. from PDF Arranger crops)
was rendered blank by --force-ocr in v16.12.0, because fix_pagepdf_boxes
offset the CropBox with the wrong sign, pushing it entirely outside the
image-page MediaBox. The behavior was fixed in v17.0.0 but had no
end-to-end test: the existing box tests only assert that ocrmypdf runs,
which the blank-page bug passed (it exited 0 with a valid, empty PDF/A).
Add a test that renders the output and asserts the visible content
survives, parametrized over both the ghostscript and pypdfium rasterizers
since the bug reproduced regardless of rasterizer.