[pytest](https://github.com/web-platform-tests/wpt/blob/7a087d54be8b6c0ca0181a86dc1ff0b28461c383/webdriver/tests/support/image.py)
uses:

    def cm_to_px(cm): return round(cm * 96 / 2.54)

[js](https://github.com/web-platform-tests/wpt/blob/7a087d54be8b6c0ca0181a86dc1ff0b28461c383/tools/wptrunner/wptrunner/print_pdf_runner.html)
uses:

    const viewport = page.getViewport({ scale: 96. / 72. });
    ...
    canvas.height = viewport.height;
    canvas.width = viewport.width;

This produces a rounding error, even though the dimension is correct:

    >       assert cm_to_px(expected_dimensions["height"]) == height
    E       assert 454 == 453
    E         +454
    E         -453

The inconsistency of rounding in both ends becomes clear when we
eliminate "round" in the pytest side:

    >       assert cm_to_px(expected_dimensions["height"]) == height
    E       assert 453.54330708661416 == 453
    E         +453.54330708661416
    E         -453

There are multiple ways to fix this issue.

Option #1: Use "floor" instead of "round" in pytest.

Option #2: Use a range in the assertion comparison, allowing a
difference of up to +-1.0. This is what this PR does.

The comparison is performed in
[`assert_pdf_dimensions`](https://github.com/web-platform-tests/wpt/blob/b6107cc1ac8b9c2800b4c8e58af719b8e4d9b8db/webdriver/tests/support/fixtures_bidi.py#L210).

The problematic part is .96 / .72 which evaluates to 4/3 = 1.333333....

This reverts commit 63f894e.

This reverts commit 7e65d91.