Tests whether mixed values are reported properly.
On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
Role: AXRole: AXRadioButton
Mixed: false
Role: AXRole: AXRadioMenuItem
Role: AXRole: AXCheckBox
Mixed: true
Role: AXRole: AXCheckMenuItem
PASS successfullyParsed is true
TEST COMPLETE