iter_markers order is top-to-bottom at module node/scope

Not entirely sure if it would be considered a bug, but it surprised me. I expect iter_markers to return the markers in bottom-to-top order (outwards from the test), but for the pytestmark variable this is not the case, it returns them in the list order.

import pytest

pytestmark = [
    pytest.mark.order(4),
    pytest.mark.order(3),
]

@pytest.mark.order(2)
@pytest.mark.order(1)
def test_marker(request):
    lowest = 0
    for mark in request.node.iter_markers("order"):
        order = mark.args[0]
        assert order > lowest
        lowest = order

FAILED test_marker.py::test_marker - assert 3 > 4

I expect this will also apply for pytestmark as a class variable.

Start with the reproducer in the issue and trace request.node.iter_markers("order") for module-level pytestmark, then check whether class-level pytestmark follows the same path. Done means the marker sequence is bottom-to-top as expected while preserving the existing test-marker behavior; add or update coverage for the shown module and class cases.