This tests that aria-multiselectable is exposed correctly for grids.

PASS: gridMultiselectableUnspecified.isMultiSelectable === true
PASS: gridMultiselectableTrue.isMultiSelectable === true
PASS: gridMultiselectableFalse.isMultiSelectable === false

Updating aria-multiselectable for #grid3 from false to true.
PASS: accessibilityController.accessibleElementById('grid3').isMultiSelectable === true

PASS successfullyParsed is true

TEST COMPLETE