Regression test `combobox_grid-combo > Home from focus on list puts focus on grid and moves cursor` failing on macOS

[howard-e]

First noticed when running the regression tests locally on #2055.

The following assertion is confirmed as failing on macOS Big Sur & macOS Monterey:

aria-practices/test/tests/combobox_grid-combo.js

Lines 880 to 883 in b62ebaf

	t.true(
	await confirmCursorIndex(t, ex.comboboxSelector, 0),
	'Cursor should be at index 0 after one ARROW_HOME key'
	);

Output:

not ok 133 - combobox_grid-combo › combobox/grid-combo.html [data-test-id="popup-key-home"]: Home from focus on list puts focus on grid and moves cursor
  ---
    name: AssertionError
    message: Cursor should be at index 0 after one ARROW_HOME key
    assertion: 'true'
    values:
      'Value is not `true`:': 'false'
    at: |-
      test/tests/combobox_grid-combo.js:880:11
      runMicrotasks (<anonymous>)
  ...